While he was imprisoned, disgraced financier Jeffrey Epstein sent a letter to Larry Nassar, the former Olympic doctor who sexually abused girls for decades, new documents reveal.

The Associated Press first reported the discovery, which was found in the midst of over 4,000 pages of documents the news agency obtained nearly four years after Epstein, who was accused of child sex trafficking, died of an apparent suicide in a New York City jail cell while awaiting trial. The new documents offer additional insight into what documents previously released by the Federal Bureau of Prisons (BOP) in 2021 revealed about Epstein's suicide.

The documents were acquired from the BOP under the Freedom of Information Act and shed light on Epstein's death and his behavior during his 36 days at the Metropolitan Correctional Center (MCC), including his attempt to connect with Nassar, according to the AP.

An investigator discovered Epstein's letter to Nassar in the jail mail room weeks after Epstein was found dead, according to the documents. The letter was not part of the documents obtained by either the AP or CNN, but the documents reference that the letter was returned to the jail in September 2019, weeks after Epstein's death.

"It appeared he mailed it out and it was returned back to him," the investigator told a prison official in an email included in the documents. "I am not sure if I should open it or should we hand it over to anyone?"

The copy of the email exchange obtained by CNN is redacted and does not reference Nassar by name. But in their reply, an MCC staff attorney described the original addressee of Epstein's letter as "the former doctor for the U.S. Female Gymnastics Team that was convicted of molesting a bunch of girls...under the guide of "medical procedures/examinations." The attorney added, "some of the victim accounts are pretty horrific."

It is unclear if the two men had any relationship.

The State Appellate Defender Office "is not aware of any relationship between Mr. Nassar and Jeffrey Epstein," Jonathan Sacks, director of the State Appellate Defender Office where Nassar's court-appointed attorney, Jacqueline McCann, works, told CNN.

The office also said it had no knowledge of the letter or Epstein's attempt to contact Nassar.

Nassar, the longtime doctor for the USA gymnastics team and Michigan State University, is serving a 60-year sentence in federal prison on child pornography charges. He also was sentenced in 2018 to a 40-to-175 year state prison sentence in Michigan after pleading guilty to seven counts of criminal sexual conduct.

More than 150 women and girls -- including Olympic gold medalists Aly Raisman and McKayla Maroney -- publicly told a court he sexually abused them. USA Gymnastics, the US Olympic and Paralympic Committee and their insurers agreed to pay $380 million in a settlement with Nassar's victims.

Epstein was charged in 2019 with having operated a sex trafficking ring in which he sexually abused dozens of underage girls -- allegations that had circulated around the politically connected businessman for years.

According to the criminal indictment, between 2002 and 2005, Epstein ran a trafficking enterprise in which he paid hundreds of dollars in cash to girls as young as 14 to have sex with him at his Upper East Side home and his estate in Palm Beach. He worked with employees and associates, according to the indictment, to lure the girls to his residences and paid some of his victims to recruit other girls for him to abuse.

Epstein's attorneys did not respond to CNN's request for comment on the letter.

Procedural mistakes by BOP staffers prior to Epstein's death

The release of the documents provides new perspectives on the obscure circumstances surrounding Epstein's time in jail, his last days alive and his suicide.

They include "a detailed psychological reconstruction of the events leading to Epstein's suicide, as well as his health history, internal agency reports, emails, memos and other records," according to the AP.

The new documents offer additional insight to what previously released documents from the BOP revealed about Epstein's suicide, including his denial that he had suicidal thoughts, despite some prison staffers noting signs of troubling behavior.

When Epstein arrived at the MCC on July 6, 2019, according to previously released BOP documents, a facilities assistant is noted in a report as describing Epstein as "distraught, sad, and a little confused." The assistant said in the report Epstein told her he was OK, but she was not convinced of this, writing that "he seems dazed and withdrawn." She advised in an email that a psychologist come and talk with him to "just be on the safe side and prevent any suicidal thoughts," but there is no evidence the email recipient, a lieutenant, contacted the on-call psychologist at the time, according to the report in the previously released BOP documents.

After a court proceeding on July 8, according to a BOP Psychological Reconstruction of Inmate Death report previously released, Epstein denied being suicidal but was placed on Psychological Observation -- less restrictive than Suicide Watch -- due to his risk factors. The next day, a BOP psychologist formally assessed Epstein's risk for suicide and determined he should remain under observation "out of an abundance of caution." On July 10, the BOP report says Epstein was taken off Psychological Observation.

In addition, BOP staff made a litany of procedural errors prior to the convicted pedophile and wealthy financier's death on August 10, 2019.

Prison guards failed to check on Epstein for several hours the night of his death by suicide, but the BOP report further notes several additional errors made by BOP staff in the time prior to his death, including inaccuracies on his screening forms.

Furthermore, a review of prison records "revealed a number of incomplete entries" with regards to provisions and receipt of basic services such as recreation, medical records, showers, and meal consumption, according to the previously released BOP documents.

The BOP report states that there were several instances where it wasn't clear if Epstein ate, took a shower or was offered recreation.

The BOP report also states that the day before his death, Epstein terminated his legal visit early to place a phone call. He told BOP staffers he was calling his mother, but records show she has been dead since at least 2004.