ABC News March 31, 2019

Karina Vetrano killing may have been carried out by 'jacked up white guys,' not suspect Chanel Lewis, according to anonymous letter

WATCH: NY jogger killed by 'jacked up white guys': Letter

Defense attorneys for a New York City man — facing the rest of his life behind bars for allegedly strangling a woman to death as she was jogging nearby her house — are expected to file a motion on Monday to request to investigate allegations from an anonymous letter that suggest details about other possible suspects were withheld.

On Thursday evening, after the attorneys in the murder trial of suspect Chanel Lewis both rested their cases, defense lawyers Julia Burke and Robert Moeller returned to their office and found a plain envelope with no return address, said a spokesman from the Legal Aid Society.

(MORE: Murder trial for suspect in Karina Vetrano killing set to begin 2 years after jogger's brutal death)

The envelope contained an anonymous letter from an alleged law enforcement source alerting defense attorneys to alleged exculpatory evidence that the author said had been withheld from the defense.

Defense attorneys said that the three-paged typed letter pointed attorneys to several meetings among investigators during the first two weeks of the probe during which -- according to unknown author of the letter -- NYPD Deputy Chief Michael Kemper "stated on several occasions at these meetings" they are "looking for two jacked up white guys who are from Howard Beach."

Charles Eckert/Newsday via AP, Pool
Defendant Chanel Lewis, right, is seated at the defense table at Supreme Court in the Queens Borough of New York, during the sixth day of his re-trial for the murder of Karina Vetrano, March 26, 2019.

The letter suggests that investigators were initially looking for one or more white assailants. Lewis, the defendant, is African-American.

"The NYPD has painstakingly investigated the murder of Karina Vetrano, and as the Queens District Attorney’s prosecution demonstrates, the evidence clearly shows that Chanel Lewis is responsible for her death," said Detective Sophia Mason, a spokeswoman with the NYPD. "Multiple legal hearings and two criminal trials, over more than two years, have already exhaustively examined the issues in this anonymous, 11th-hour letter, a missive riddled with falsehoods and inaccuracies."

"As we have throughout the course of this trial, we will respond in Court accordingly," said a spokeswoman for the Queens County District Attorney's Office.

“We received troubling and reliable information indicating that the police withheld critical Brady information about other potential suspects, which was never turned over to the defense,” Tina Luongo, a Legal Aid attorney representing Lewis, wrote in a statement released on Friday.

(MORE: Residents describe 'suspicious' activity by suspect in murder of jogger at NYC retrial)

Luongo was making reference to what's known as the 'Brady rule' that requires prosecutors to turn over any and all potentially exculpatory evidence about the defendant in a criminal case -- based on a 1963 case known as Brady vs. Maryland.

“Moreover, we learned that the police approached our Mr. Lewis to obtain a DNA swab as part of a race-biased dragnet, which involved the swabbing of over 360 African-American men in Howard Beach and other neighboring sections of Brooklyn and Queens."

(MORE: Jury selection begins in retrial of New York City man accused of killing jogger Karina Vetrano)
Seth Wenig/AP
Phillip Vetrano, father of Karina Vetrano, sits outside a courtroom in New York, March 20, 2019.

Karina Vetrano was killed while jogging in Spring Creek Park — adjacent to Howard Beach, New York — on Aug. 2, 2016. After the 30-year-old did not return home from her solo evening run — one she normally did with her father Phil Vetrano.

According to trial testimony, Phil Vetrano led the search and ultimately discovered his daughter's partially-clothed body laying in unkempt weeds in the waterfront park.

Six months into the investigation, the case had turned cold when one of the case detectives, Lt. John Russo remembered calling the police on a black man, who was roaming in the Howard Beach neighborhood three months prior to Karina Vetrano's death, according to trial testimony.

The man was later identified as Chanel Lewis.

(MORE: Dad of slain jogger Karina Vetrano says he was asked to give DNA sample at daughter's funeral)

Lewis, then 20, agreed to allow police to swab him for DNA inside his East New York home as his mother stood nearby.

Queens District Attorney’s Office
The last photo of Karina Vetrano at her Howard Beach home moments before leaving for a jog, Aug. 2, 2016, with her mother in the background.

According to the three-paged typed letter sent to the defense team, after Lewis' sample was taken, one of the detectives "reported back to Lt. John Russo the following, 'He's not the perp. He's too puny and dimwitted.'"

Nonetheless, Lewis was arrested, allegedly confessed and was charged in February 2017 with first-degree murder, second-degree murder and aggravated sexual abuse.

Lewis' first trial in November 2018 deadlocked a jury after 13 hours and prompted the case judge to declare a mistrial.

"In light of this case-altering information, we plan to submit motions on Monday seeking a hearing as to the prosecution's failure to disclose this exculpatory evidence and a new hearing challenging the [New York Police] Department’s unconstitutional racial profiling throughout their investigation,” Luongo wrote.