Jail Informant Sends NYPD Detectives on a Frantic Search for a High-Rise Crime Scene

Against the backdrop of a new millennium and Y2K fears, New York City detectives must piece together what happened to a murder victim who has yet to be found.

It was a rainy night on December 20, 1999, just days before the new year, when detectives at the Midtown South Precinct in Manhattan received a phone call at around 8:00 p.m. The call came from an inmate at Riker’s Island, which houses New York City’s largest jail, stating he had information about a possible robbery-turned-homicide, according to N.Y.P.D. Detective Artie Caddigan.

“He heard the victim was duct-taped, and he was stabbed with a knife, then he was left under a couch,” Caddigan told New York Homicide, airing Saturdays at 9/8c on Oxygen. “He believed that it happened a couple of days before he called me.”

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The inmate — whose name remained withheld by police — claimed he heard his cellmate, Paul Person, having in-depth conversations about the alleged murder over the phone. The N.Y.P.D.’s newest informant was incarcerated for a weapon possession charge and hoped to use the information as leverage for a deal.

According to the informant, Person – jailed for gun charges days earlier — instructed his girlfriend and a male friend to rob money from a specific person for Person’s bail.

The unidentified victim was believed to be a wealthy white male in possession of a large sum of cash. He allegedly took his money out of the bank for fears of Y2K, when people worried banks and other digital infrastructures would crash when the dates went to the year zero-zero when entering the year 2000, a worry that never came to fruition.

But the informant’s information was limited. He and detectives only knew the victim lived on the 42nd floor of a 45-story building in Midtown. The residence reportedly had a doorman and nearby A.T.M., and police were told the victim’s balcony door would be ajar to release the smell of decomposition.

Person’s friend and girlfriend allegedly took the subway to 50th Street, only slightly narrowing the N.Y.P.D.’s scope for where the crime scene may be.

“There were about 80 to 100 or maybe more buildings that are higher than 40 stories,” Detective George Delgrosso told New York Homicide. “It’s a needle in a haystack.”

Detectives finally caught a break when a doorman from a W. 48th Street building claimed he hadn’t seen their 42nd-story resident in days.

Who was murder victim Thierry Matheron?

Upstairs, investigators found 36-year-old Thierry Matheron deceased, his body and the crime scene staged just as the informant described. There were no signs of forced entry, and the victim — found beneath a flipped-over couch — had a kitchen knife protruding from his neck.

A post-mortem examination would reveal Matheron died by suffocation from being bound by duct tape, which was found around his mouth, nose, wrists, and ankles.

Detectives learned the affluent French-born man worked for Ernst & Young, a big name for accounting firms. With Matheron’s relatives back in Marseilles, his co-workers wondered who would want to kill someone they so cared about.

“When I heard the word ‘murdered,’ I think that just sent kind of a shockwave through me because Thierry was so well-liked in the office,” said manager and friend Lanny Cohen. “He really had compassion for people, genuine compassion. And [he] was always there to lend a helping hand without being asked.”

“I was sickened with emotion, and it felt like someone had punched me in the chest,” said colleague and friend Nydia Gaffey. “I couldn’t even breathe.”

At the crime scene, detectives found an answering machine recording from a concerned man looking for Matheron. The call came from an upstate New York prison but not from a person familiar to detectives.

A Look into the Suspects

The informant didn’t know the identities of Paul Person’s girlfriend and friend — the pair now wanted for directly killing Matheron — but he knew the male friend was referred to as “O.” Detectives looked into Person’s arrest record and identified O as Oliver Johnson.

Person and Johnson were arrested together days before Matheron's murder, stopped for a traffic infraction while purportedly en route to commit a robbery separate from the crimes against Matheron. Person, who'd fled the car and tossed a gun, was booked into Riker’s Island while Johnson walked a free man.

According to Manhattan’s Assistant District Attorney Tom Schiels, Person felt Johnson owed him.

“Person tells O, ‘If you don’t do this, I will do something terrible to your family,’” according to Schiels. “[Johnson] was afraid that, even from behind bars, Person would be able to orchestrate some injury to his family.”

The informant claimed Johnson and Person’s girlfriend robbed Matheron of his bank card and demanded the P.I.N. before killing him. When the P.I.N. failed, Person allegedly sent the pair back to Matheron’s apartment to kill again.

“Person instructed O to ‘go back, burn down the apartment to cover up any fingerprints, and kill the doorman, because he could identify you and my girlfriend, and therefore, leading them back to me,’” according to Schiels.

Thankfully, police caught wind of the hit before the doorman could be harmed.

Cops soon identified Person’s girlfriend and Johnson’s alleged accomplice as Nakia Shannon, arresting her at her Queens home just days after Matheron’s murder. According to a videotaped interview published by New York Homicide, Shannon said Person — the father of her child — had nothing to do with the crime and that it was all Johnson.

“He said, ‘Don’t hurt me, you can have my money,’” Shannon said of the victim.

With Shannon’s help, they found Johnson at his girlfriend’s home in the Bronx.

Johnson denied his role in Matheron’s murder until confronted with Shannon’s confession.

“I was forced into the situation,” he said. “Nakia and Paul kept on calling me to threaten me.”

Why Did Person, Johnson, and Shannon target Matheron?

Johnson claimed he met Matheron through another inmate named Steven Lee, Johnson’s former cellmate who was incarcerated upstate for a parole violation. Lee was a houseless sex worker who’d met Matheron at Port Authority before Matheron and Lee entered a sexual relationship.

Johnson said, over time, Matheron wanted Lee to move in, but only after he faced the consequences of a previous robbery charge. Through Lee, Johnson met Matheron several times when Matheron visited Lee in prison

“Mr. Matheron had Steven turn himself in to clear up his parole violation, and he was going to let him come to live with him when he got out of prison,” A.D.A. Schiels told New York Homicide.

Lee told Johnson about Matheron's alleged Y2K cash, but not with intentions to harm Matheron. 

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Johnson and Shannon confessed they went went to Matheron’s apartment after concocting a lie about wanting to bring a pair of shoes for Lee. According to the suspects, Matheron was on the phone with Lee just before Johnson killed Matheron while Shannon held the victim up at gunpoint. 

Detectives don’t believe Lee was in on the crimes, having tried to call Matheron numerous times after the murder. In fact, it was a concerned Lee who’d left messages on Matheron’s answering machine shortly after the murder.

“He [Lee] was truly grief-stricken by the loss of Mr. Matheron,” said A.D.A. Schiels.

Matheron’s rumored Y2K cash was never found, and the suspects made off with $40 from the victim’s wallet.

Arrests and Convictions

Despite a court order to keep Paul Person in jail as the murder investigation continued, he was mistakenly released around the same time as the N.Y.P.D.’s confidential informant.

The informant was in and out of touch with police, claiming Person insisted they meet in face-to-face. Fearing Person knew the informant ratted him out, they advised him not to meet Person on the outside.

“Then one evening, he calls the precinct and says he’s in Queens with Paul Person at a barbershop,” Schiels told New York Homicide. “And the detective who answered the phone call is dumbfounded by this.”

The informant said he was with Person and in the process of robbing the barber at gunpoint.

Contact was lost until the following day, when cops in Queens reported the informant in custody after the barbershop theft. Much to detectives’ disbelief, the informant claimed he had to go through with the armed robbery and was working “deep undercover” for them.

Person evaded capture, but the informant helped police find him in a Harlem apartment.

Person was uncooperative with police about the Matheron homicide investigation, though in exchange for a plea deal, Johnson and Shannon testified against Person.

Oliver Johnson and Nakia Shannon were convicted of second-degree murder, with Johnson sentenced to 15 years to life and Shannon spending six years behind bars.

Person was charged with first-degree robbery, felony murder, and intentional murder. However, in 2003, a jury found him not guilty of the murder charges. He was convicted only for the robbery charges and sentenced to 25 years in prison.

“It was obviously a good feeling to know the investigation ended with everybody involved being convicted,” said Det. Artie Caddigan. “It was justice for our victim and his family.”

“Thierry just had a presence and a personality about him that was so endearing that there was a chunk of all of us that got lost when we lost Thierry,” recalled friend Lanny Cohen. “Some part of this world isn’t where it needs to be because Thierry’s not in it.”

The confidential informant served time for the barbershop robbery and testified in Person’s murder trial. He has since changed his life’s course, working as an apartment building porter and is described as being on “the straight and narrow,” according to Caddigan.

Johnson, Shannon, and Nakia completed their sentences and have since been released from prison.

Watch all-new episodes of New York Homicide as Season 2 continues, airing Saturdays at 9/8c on Oxygen.