Jeffrey Epstein’s death in prison was a suicide, the medical examiner said on Friday.

Epstein was arrested in July on federal sex trafficking and conspiracy charges relating to the alleged abuse of hundreds of young girls. The billionaire sex offender was found dead at the New York Metropolitan correctional center (MCC) this month.

A spokeswoman for the New York City Office of Chief Medical Examiner said that an autopsy had concluded that the cause of death was suicide by hanging. An official report on Epstein’s death would be disclosed on Friday, Aja Worthy-Davis added.

Since the billionaire’s death, serious questions have arisen about conditions at the Manhattan jail where he was held, and there was widespread speculation about the circumstances of his death.

The FBI and the justice department are investigating the incident, and the attorney general, William Barr, said officials had uncovered “serious irregularities” at the facility.

Two guards assigned to watch Epstein have been placed on leave and the warden has been temporarily reassigned.

The guards were required to make separate checks on all prisoners every 30 minutes but that procedure was not followed the night before Epstein was found dead. The guards are now suspected of falsifying log entries to show they were making the checks. Surveillance video showed that guards never made some of the checks noted in the log, a source told the Associated Press.

Epstein had been placed on suicide watch after a previous incident in the jail but had been later taken off suicide watch.

On Thursday, the Washington Post and New York Times reported that the autopsy had shown several bones in Epstein’s neck had been broken, which raised further questions about how he died.

The Post cited an expert who said that a broken hyoid bone “can be broken in many circumstances but is more commonly associated with homicidal strangulation than suicidal hanging”. The expert later clarified his statement in a press release, saying that a “hyoid fracture is not a definitive finding that by itself determines if a death was a homicide, or by itself distinguishes a homicidal strangulation from a suicidal hanging”. The expert pointed out that such broken bones were more common “with increasing age”.

Jonathan Arden, the sole forensic expert WaPo quoted in its Epstein report, has put out a press release saying hyoid bone fractures are "well recognized" to occur in suicidal hangings, and stresses importance of interpreting things in "context of the totality of all the findings" pic.twitter.com/KxVajCml71 — Oliver Darcy (@oliverdarcy) August 16, 2019

In response to those reports, the chief medical examiner, Barbara Sampson, said: “In all forensic investigations, all information must be synthesized to determine the cause and manner of death. Everything must be consistent; no single finding can be evaluated in a vacuum.”

Lawyers for Epstein said in a statement Friday they are dissatisfied with the medical examiner’s conclusions and plan to view prison videos themselves from a facility operating under “medieval conditions” .

The medical examiner’s statement also followed a new sexual abuse lawsuit filed by two unidentified women in a Manhattan district court. The complaint, filed by the civil rights lawyer Lisa Bloom, targets Epstein’s estate and an alleged “recruiter” and demands $100m in damages.

In 2004, the unnamed “recruiter” lured the two women into Epstein’s New York mansion, where he sexually assaulted them, according to the suit filed Thursday night.

Vivian Ho and agencies contributed to this report