Original subtitles

There is a pattern of vibrant, independent women

who are just dropping dead.

Nobody had worked a case of this magnitude.

This is a man who maybe in his life

did not have a lot of power.

It was unthinkable.

He was an incredibly prolific killer.

There can be hundreds of people that he murdered.

Truly, he's a monster.

Preston Place is a very nice, upscale retirement community

in Plano, just north of Dallas.

It was for active elderly individuals.

My mother, Mary, lived in this community.

She'd go to exercise class with her buddies,

and they had all these social events they would go to, too.

It was a tight-knit community, and my mother, Ann,

she really enjoyed living at Preston Place.

The Dallas metro area, including Plano,

has several of these upscale independent-living places.

The reputation that they're safe spaces,

safer than your home.

In March of 2018,

I was assigned to a case that involved the theft of jewelry

from a recent deceased person--

Martha Williams, 80 years old,

who lived at Preston Place.

Martha Williams' family reported about $7,600 worth

of gold and silver were missing,

including a wedding ring

that they said she would never take off.

I wanted to know more about the actual death investigation,

which was handled by another detective.

So I start looking at the report.

Martha Williams' death was deemed from the M.E.'s office

to be an unattended natural death.

There's nothing suspicious about it.

They call these unattended deaths

because they were discovered deceased.

There's no one that actually witnesses the death.

So on the photos you see

Martha's found on the floor by the side of the bed.

She has her shirt pulled up over the top of her head,

and there was makeup on the back of her shirt.

That looked like a struggle had occurred.

And then to have a report of jewelry stolen

on top of that, I thought it was... suspicious.

According to her family,

Martha Williams was married for 42 years and widowed.

But she was not just someone who was unhealthy waiting to die.

Martha was friends with my mother, Ann.

So when Martha died, we were all really upset.

She just didn't seem ready to die.

She was vibrant.

At that point,

the supposition was that it's a theft from a deceased person.

We had to look at everybody from the first responders,

the funeral home to the staff at Preston Place.

And when I started to do more investigation

into Preston Place,

this wasn't just theft from a deceased person.

Something else is actually going on.

I found that there were multiple deaths at the same location

in the last few months.

From Halloween to December 2017,

there were three unattended deaths.

Martha Williams... that's four within a 5-month span

at the same facility.

We found out before these deaths, Preston Place,

they hadn't had a death at their facility in three years.

I find that very suspicious.

So I started looking through the reports.

All of these cases were elderly women in good health

that appeared to have died of natural causes.

These individuals were found either laying on a bed

or on the ground right next to the bed.

None of the apartments that were in question

appeared to be broken into.

In fact, the doors were locked.

All of them lived by themselves.

Some had recently been widowed.

These individuals, they were very active.

These three other incidents that have occurred in the past,

very similar description to the Martha Williams case.

The only thing was that jewelry was not reported missing.

We go back and talk to those families again,

and sure enough,

those families had since noticed the missing jewelry.

At that moment, we realized, "Oh, boy."

"These cases got to be connected."

We believe that possibly we had a serial killer.

It seems reasonable to consider

there is a serial killer, not just a thief.

Somebody who is repeatedly killing similar types of victims

with the same M.O.

What seems most obvious is there was some type

of money motivation.

That's very unique for serial killers.

I do wonder if committing these killings

of very helpless victims,

is that gratifying to think about their power over them?

This is someone who maybe in their life

did not have a lot of power.

It is just a very sad situation.

We've got someone that's preying on our most vulnerable citizens.

His chosen victim population is much older

than most serial killers.

One theory might be that the killer targeted the elderly

because he understood

that perhaps they are not often investigated

when they pass away.

When you're dealing with an elderly individual,

there's different protocols

that the medical examiner's office can follow.

If there is no sign of foul play,

then the protocol was to not do an autopsy.

The first three deaths,

all the evidence is gone because most of these people

have been embalmed and buried or cremated.

There wasn't any type of forensic evidence

these ladies were being murdered.

The M.E.'s office examined Martha Williams.

She had makeup on the back of her shirt,

which could indicate that she was smothered.

A smothering death, there's going to be petechiae,

which is the bursting of small blood vessels around the eyes.

Unfortunately, sometimes you can get those as an elderly person

through natural means as well, so it's not conclusive.

This killer was savvy enough to not leave

obvious signs of homicide.

He left the scene in a way that was not disturbed.

Locking the door when he left.

And he definitely left a lot of jewelry behind.

He knew that that would lower a suspicion.

Serial killers do evolve.

They learn what works, what doesn't work.

They might change their behavior

to become undetectable over time.

He might have committed other murders.

We reached out to other area agencies

to see if they had anything like this going on,

but no one else was looking at this at the time.

We just felt like it's never going to stop and it didn't.

While our department is looking into these other cases,

trying to determine what is going on,

we get another unattended death at Preston Place.

81-year-old Miriam Nelson.

Miriam Nelson's daughter Karen

found her on the bed deceased at Preston Place.

She said that she doesn't believe

that her mother just died of natural causes.

The family is reporting

that there's $11,000 worth of jewelry missing.

That's two murders over three days.

To me,

that rapid succession in the one murder after the next,

I would be concerned at that point

that it would escalate and go faster and faster.

There was this predator out there stalking their loved ones.

My mother's on the floor, face down.

She isn't moving. And I start screaming.

Now we have another deceased person across the hall.

It was shocking.

We needed to stop him from killing more.

In March 2018,

the Plano Police Department has five unattended deaths

in a 5-month span at the Preston Place.

These are not nursing homes.

These are really upscale, almost country-club-type facilities.

And there is a pattern of vibrant,

independent women who lived alone,

who are just dropping dead.

And at the same time,

valuables are missing from their apartments.

If you start having deaths on property, the word will get out.

And the residents at Preston Place,

they were very tight-knit group of people.

My mother, Ann, she would go work out every morning and say,

"Oh, there's a lot of gossip about stolen jewelry

and some people dying."

And we would dismiss it like, "No, this is craziness."

She just felt safe.

I thought my mother was completely safe

at Preston Place.

That somebody would just attack elderly women,

it just doesn't seem like it's possible.

These families didn't want to think the worst,

but there was this predator out there that was stalking

their loved ones.

We're trying to stop more deaths from occurring.

And luckily for the investigation,

one of the family members of Miriam Nelson

told detectives Miriam had told her family about someone

who came to her apartment posing as a maintenance person.

This man enters her apartment and tells her

that he's there to inspect the water heater.

Miriam thinks that he may have taken some

of her jewelry at that point.

The front desk told Miriam

that there was no maintenance man sent to her room.

It really terrified her.

And then, unfortunately, two days later,

Miriam is discovered deceased.

Her family told the investigators that Miriam

had described this person as a well-dressed, bald, black male.

It's possible that the same man came back and killed her,

and possibly he did so

because he knew she would be able to recognize him.

We needed to talk to this man

who came to her room two days before she was found dead.

The management company told the police

there was no one matching that description working

at Preston Place.

We knew that this was probably somebody

that was from outside of Preston Place.

A lot of people who are able to commit these type of acts,

psychopaths, they can all appear very normal,

very typical, you know, personable.

That's how serial killers are able to hide in plain sight.

At that point, we had not yet put it into the press.

As a police department, you want people to be safe,

but you also don't want to cause panic.

But everybody in that community

was now aware they needed to be on the lookout

for suspicious activity.

The residents had a description of the person posing

as a maintenance man.

We set up a crime tip line and sure enough,

we got a report of suspicious persons in the area.

One of the resident's sons, Richard Plank,

he knew about the deaths,

and he noticed that there was a suspicious vehicle

that had been parked in the parking lot

with a male sitting in the vehicle.

What made this suspicious

is that Mr. Plank thought the man was

a very similar description to the man

that pretended to be a maintenance guy.

So much so that he took the license plate down.

He then called it into the police.

When we run this car, there's a plate.

We also pulled up the driver's license,

and we learned that the driver of this vehicle

was someone named Billy Chemirmir.

Now we needed to figure out,

is this a serial killer or is he just a guy

that is sitting in a car?

And we start researching.

Billy Chemirmir, 45 years old,

is from the Rift Valley in Kenya.

In 2005, he came over to work in the United States.

He's a caregiver for the elderly.

Mr. Chemirmir did work in the healthcare industry.

It could have been that he was at Preston Place legitimately.

However, we found that he had been arrested for DWI

and public intoxication.

Also, he was arrested in 2016

for the criminal trespass at Tradition-Prestonwood,

another affluent retirement community in Dallas.

Billy Chemirmir tried to claim that he had clients there,

but they found out that that was not true.

Criminal trespass is a misdemeanor,

but that was very suspicious.

The Plano Police Department had developed

Billy Chemirmir as an individual that they wanted to talk to.

This is all hands on deck.

But at the same time we're trying to find Billy Chemirmir,

Plano Police Department gets another 911 call.

The Plano Police Department were investigating five deaths

of women in a short amount of time at Preston Place

when they got another 911 call.

On March 19, 2018,

the day after we start looking for a possible suspect,

Billy Chemirmir, one of the residents from Preston Place

has found her friend Mary Bartel unresponsive.

Miss Bartel was supposed to go to an exercise class

that morning when her neighbors came by to pick her up.

They knocked on the door. She didn't answer.

The door was unlocked, so they entered the apartment

and they found Mary unconscious on the bed

and immediately called 911.

The fire department responds

and they transport her to a hospital in Plano.

My mother, Mary, she had just turned 91.

She's still going strong. She's exercising.

She's going to church every day.

My mother was born on a farm in Illinois.

She knew my dad through 4-H.

They got married in 1948. She had six kids.

And then she became a teacher.

They were very happy.

My parents were married for 67 years

when my dad passed in 2015.

My mother, she was sad.

She missed him for sure,

but we were nearby and for her, she just...

she liked to be with family.

Immediately we went to the hospital.

This is...

The first responders,

they were able to get Mary Bartel back.

It was just such a relief

because my mother was sitting up in bed and she seemed cheerful.

But then she told us someone attacked her.

Mary Bartel reported that a man had taken a pillow

and tried to suffocate her.

Mary Bartel is possibly the sixth victim

of the serial killer.

And now we've got a living witness.

Not knowing who was on the other side, she opened the door.

An individual forced her into her apartment.

Through talking to Miss Bartel, we believe

that the serial killer's weapon of choice was a pillow.

We knew she had been attacked.

But also, there is jewelry missing.

The intruder took the jewelry off her finger.

What's the value of a human life?

I would hope it's a lot more than that.

She described him as a black male with green gloves,

but that was it.

Mary is describing exactly what we thought was happening.

He was speeding up.

At that point, he was probably really feeling very invincible,

so he was taking more risks.

Opportunistic offenders can be extremely impulsive

if a situation does arise.

So this is all happening at the same time

we have officers out there looking for Billy Chemirmir,

and we send officers out to Mary Bartel's apartment

to secure it.

While our investigative team

is at Mary Bartel's apartment at Preston Place,

the officers, they see a woman going across the hallway

to another apartment.

On that Monday, March 19,

I went to go get my mother

and when I get there, the police were all over.

This is odd, but I don't put two and two together at all.

She goes into the apartment

and immediately the officers hear this blood-curdling scream.

We're investigating Mary Bartel's attempted murder

at Preston Place.

While she's being treated in the hospital,

investigators are at Mary Bartel's apartment

to find evidence.

At that time,

Ann Conklin's daughter comes over to her mother's apartment,

which was located directly across the hall

from Mary Bartel.

My mother never locked her door,

but that day the door was locked

and something just doesn't feel right.

I insert the keys, turn it and it's dark,

but I can see my mother's on the floor, face down,

and I can see that she isn't moving and start screaming.

I run into a policeman. I'm frantic.

So he goes into the apartment,

comes back out, and I said, "Is she okay?"

And he's like, "No, she's passed."

My mom, 82, just passed away.

I don't understand this.

She was incredibly healthy.

My mom's old TAG watch

and my mom's diamond solitaire necklace are missing

that she always wore.

The police, they're thinking

that Mom might have been attacked

and that her stuff was stolen.

Now we have another deceased person across the hall

from the attempted murder that we're investigating.

It was shocking.

We needed to stop him from killing more.

My mother was an incredibly bright,

beautiful, accomplished woman.

She had been there and done that in every capacity,

be it travel, education, work.

And then it was just time to make a change.

We sold her house and I was very excited about Preston Place

because it was literally a three fourths of a mile from my house.

I got to spend a lot of time with her,

and for that I'm so thankful.

Billy Chemirmir had been seen by Mr. Plank at Preston Place,

and he was a very similar description to what

Miriam Nelson had told her family

two days prior to her death.

He was the only lead that we have at this point.

As we're continuing to investigate,

we find out that Billy Chemirmir may be living

in this apartment complex in Dallas,

and so our team goes to that location.

He wasn't at home, so they just wait.

So while we're trying to track him,

I went and searched online.

I was very familiar with resale platforms.

can be a platform where a lot of stolen items show up.

Because once an item is sold,

it'll only remain publicly for a short period of time.

And then it's gone.

Detective Hoffman looked, and he found a ring on

that resembled what Miss Bartel had said was stolen.

Miss Bartel's son had e-mailed me a picture,

and it looks exactly like Miss Bartel's ring.

This listed almost immediately after Miss Bartel's victimized,

and it's on the finger of a African American male.

The ring was placed on OfferUp by Zebzeb4.

We subpoenaed for these records.

With the subpoena, we get e-mail information.

I take the e-mail address,

plug it into one of our law-enforcement apps.

And guess what? It's Billy Chemirmir.

The Plano Police Department had set up

on Billy Chemirmir's apartment

with a number of detectives hoping for him to come home.

And they're waiting and they're waiting.

And then a guy comes driving through that

closely resembles the description,

but he drives over to a Dumpster.

This man throws this red box into the Dumpster.

He leaves the Dumpster

and the officers converge on this car.

And Billy Chemirmir is just dumbfounded.

They take him into custody

and they go back and they search the Dumpster

to see what it is he threw away.

They find this beautiful red jewelry box.

It had information inside the box.

Her name, address, that it belonged to Miss Lu Thi Harris.

We found out that Lu Thi Harris was 81 years old.

She was living at a house in Dallas.

We know that there's possibly another victim,

and that is a hard pill to swallow.

They immediately alerted the Dallas Police Department

to go do a welfare check.

When the Dallas Police Department arrives

at Lu Thi Harris' house, it's completely locked.

No one's coming to the door.

So they make entry through the back.

They find Miss Harris dead next to her bed.

So we've got two deaths

and an attempted murder within the same couple of days.

I was in utter shock.

Like, truly, he's a monster.

I couldn't believe it.

She was murdered just a couple of hours before we arrested him.

Now everybody's starting to realize this is bigger

than Preston Place.

How many people is he responsible for killing?

While Mr. Chemirmir is brought

into the Dallas Police Department,

the police start to investigate Miss Harris' death.

They found a pillow next to the body

with makeup smeared on the pillowcase,

leading us to believe that Billy Chemirmir

had used that pillow to suffocate Miss Lu Thi Harris.

Because there was fresh groceries in her kitchen,

and they find the receipt, detectives determined

that she had just gone grocery shopping at the Walmart

that was about a mile away from her house.

It was a possibility

that Mr. Chemirmir followed Miss Harris home.

So detectives go to the Walmart to get surveillance footage.

When we look at the video,

Miss Harris is seen, and then he's just following her.

He gets very close to Lu Thi Harris

several times.

He's hunting when he's doing this.

You wouldn't think anything suspicious about him

if you saw him walking next to you.

He was just a normal-looking individual.

He leaves first and a short period of time later,

she leaves and Miss Harris isn't seen alive again.

The next day, Mr. Chemirmir is questioned

by the Dallas Police Department and the Plano Police Department.

We had been tracking Billy Chemirmir for two days.

We believe he was a serial killer.

And that was killing women for their jewelry.

Now he's in our custody,

and he was being interviewed at Plano Police Department.

He was very adamant that he didn't do anything wrong.

I don't think I've ever seen anybody in my career

who had so much to lose

be so cool and collected.

After the interrogation,

Mr. Chemirmir voluntarily gave his cellphone.

He was like, "Yeah, search it.

It'll prove me innocent."

This man comes off as trying to be helpful.

I think for Billy Chemirmir,

that is an attempt to join with the detectives,

put on a good-guy facade to try to be likable.

People who are able to commit these type of acts

are master manipulators.

That's what helps them fly under the radar.

His cellphone helped us get the data

that we needed to track him and find out everywhere he's been,

and we start figuring out, click, click, click.

He's at Preston Place

during the time of all of these unattended deaths.

We subpoenaed the records from OfferUp.

So we cross-referenced

that information with the location data.

And he has a ton of women's jewelry listed

that has sold or being sold, and it goes back years.

That was where we truly got a story of how vast this might be.

There could be hundreds of people that he did this to.

Now we needed to set up a task force.

Nobody had worked a case of this magnitude.

When police arrested 45-year-old Billy Chemirmir

on Tuesday, it was for the murder of an 81-year-old woman.

Now authorities say he could be a suspect in others.

This is very early stages of a very large

and complex investigation that covers multiple jurisdictions.

We were looking at all unattended deaths

in the Dallas and Collin County areas

going back to the beginning of 2016.

We ended up having to review over 700 unattended deaths.

As the investigation progressed,

we found an enormous amount of deaths

that had evidence linking back to Billy Chemirmir.

We were able to put Mr. Chemirmir at the location

of the offense,

and we had him selling the jewelry items

that belonged to the victims in a close proximity of time.

Luckily for the investigation,

he doesn't wait weeks or days to sell.

He waits hours.

We worked on this case nonstop for a year.

In the end of it,

Billy Chemirmir was indicted on 22 capital-murder charges.

The first two murders that were known

and are recognized by the Dallas DA's office

occurred in Edgemere in 2016,

which is in a very upscale part of Dallas.

And then he moved on to North Dallas

at a place called Tradition-Prestonwood.

So there's eight deaths there

and three at the next one in Frisco.

And then you have seven women killed at Preston Place.

In addition to these facilities that were targeted,

there were four in private homes in the same general area.

The sheer number that's involved here,

yeah, it won't be forgotten anytime soon.

That's what we had good enough to make cases on.

Google location technology

wasn't available to us before 2016.

What was he doing before that?

In my opinion, based on investigation,

I would say 75 is a realistic number

and probably conservative.

He was an incredibly prolific killer.

How does such evil exist?

This was a pretty unique case when it comes to serial killers.

Typically, you think of someone

who's out there preying on people

to satisfy some sort of sexual motivation.

This was clearly something else.

This was a person who was motivated by the money.

But we don't know where he got the idea to start

to kill elderly women.

Mr. Chemirmir did work in the healthcare industry.

He did have clients.

Every person that he took care of

that wasn't a victim

knew him as a loving, caring guy.

We were able to talk to family members of Mr. Chemirmir's,

and we learned that he came from a very large family in Kenya.

He actually came from a well-to-do family.

His father was a chief in the area.

We don't know why Billy Chemirmir

comes to America, but there were suggestions

that he had had alcohol problems in Kenya

that caused estrangement from the rest of his family.

From what we could tell, he lived a pretty modest lifestyle.

But we discovered during the investigation

that he frequented African nightclubs.

After interviewing people who knew him from the nightclubs,

we learned that he wanted to be recognized as a high roller.

He would tip the waitresses hundreds of dollars

and buy rounds of drinks for everybody.

This is a man in his life

that did not appear to have a lot of power,

but he came from a very powerful family,

and perhaps what he really wanted to be was to be revered,

to be esteemed, to have high social clout.

He wanted that social perception,

and he murdered people to make that money

so he can go to the club and catch somebody's eye.

That's it.

But he was only tried for the case of Lu Harris.

She was found in her house back in 2018.

The only statement Mr. Chemirmir ever made

was just stating that he was not guilty of these offenses.

Lu Thi Harris was the most powerful evidence we had.

During the investigation,

we found Billy Chemirmir's DNA on Lu Thi Harris' pillow.

The pillow was indeed the smoking gun.

This is a case about stalking,

smothering and stealing.

The trial was in 2021.

Normally, you're not allowed to talk about other bad acts

that an individual has done,

but because of the manner of the offense,

we were able to bring in Miss Bartel's case

and Martha Williams' case to show that there's a pattern.

I was very confident that we would get a guilty.

We remain deadlocked at 11 to 1.

There was one person who just could not convict him.

After four days,

the trial of Billy Chemirmir goes to the jury

for Miss Lu Thi Harris.

It's one of the cases where you would think this is a slam dunk.

Ultimately, we were informed

that they could not reach a verdict.

This trial has occurred-- Or a hung jury has occurred.

So the very first trial was a mistrial.

It was beyond confusing

because there was such a prolific amount of evidence

that it was-- it was crazy.

And you're just devastated.

The first trial, COVID restrictions

were still in place.

The jury had to be separated.

So it was a bit difficult.

But we turned right around and tried Miss Harris' case again.

This time, the jury convicted Mr. Chemirmir.

This man was one of the worst serial killers

this century.

In Texas, that means that he will be serving a life

without the possibility of parole.

He's suspected of killing 22 elderly women in North Texas,

but has so far been convicted of one murder.

Unfortunately, not every victim's family

got to have Mr. Chemirmir answer

for the death of their loved one.

So all indicted victims' families

were given the opportunity to address the defendant.

We have all been living in a nightmare,

and every single one of us just wants to wake up and we can't.

You have no heart. You have no soul.

You have no conscience. You have no dignity.

All these moms were so precious.

The opposite word of precious is worthless.

And that is you.

There was no real sign that he was remorseful,

and despite the huge amount of evidence,

he never admitted to these murders.

Some serial killers will eventually admit

because they want acknowledgment.

They're proud of the killings.

Perhaps Billy Chemirmir, what he wanted other people to see

was that man in the club who was powerful,

who had money, and he, in the end,

didn't feel fulfilled by being known as a killer.

Something broke in him

and he started killing people and stealing their jewelry.

Why? We still don't know.

And we will never know because he's dead.

It took my breath away.

You just..."Wow."

It's over.

There will never be an escape from prison.

There will never be a retrial.

It was over.

And you have to tell the story because it deserves to be told.

My mom, Mary, she passed away in 2020.

I was really proud of my mother that she survived,

but also that she told a coherent story

that told them exactly what was happening.

She was always independent.

She was the leader of the family,

and she was always so strong.

Someone who was born a very poor farm family

who ends up taking down a serial killer.