Jeffrey Epstein's cause of death was suicide by hanging, the New York City Office of the Chief Medical Examiner said Friday.
Hours later, Epstein's attorneys said they will conduct their own investigation into the circumstances of his death.
The medical examiner's determination came almost a week after the multimillionaire was found in his cell at the Metropolitan Correctional Center, where the 66-year-old was awaiting trial on federal charges accusing him of sexually abusing underage girls and running a sex trafficking ring. He had pleaded not guilty to the charges.
The autopsy was performed Sunday, the chief medical examiner's office said in a statement at the time, but its findings were pending further information. A private pathologist also observed the autopsy, the statement said, calling it "routine practice."
Both the FBI and the Justice Department's Inspector General are investigating the circumstances around the accused sex trafficker's death.
Epstein's lawyers said they are not satisfied with the medical examiner's conclusions and urged more scrutiny of the jail.
"No one should die in jail. And no one, not Mr. Epstein who was presumed innocent and had violated no prison disciplinary rule, and not anyone should be imprisoned under the harsh, even medieval conditions at the MCC where Mr. Epstein spent his final hours," they said. "His safety was the responsibility of the MCC. It is indisputable that the authorities violated their own protocols."
US Attorney General William Barr said earlier this week that there were "serious irregularities" at the facility where Epstein was held.
Epstein was placed on suicide watch following an incident last month at the jail. But in late July, after he was given daily psychological assessments, he was taken off suicide watch and returned to the special housing unit, according to a person briefed on the matter.
Two prison staff members guarding Epstein's unit failed to check on him that night for about three hours, The New York Times reported Tuesday, citing several law enforcement and prison officials with knowledge of the investigation.
Officials have cautioned to CNN that they don't know what the staff members were doing during that time and are still trying to pin that down.
Guards are supposed to check on detainees in the special housing unit every 30 minutes, a source with knowledge of Epstein's time at the prison previously told CNN.
It's protocol for detainees coming off suicide watch not to be placed alone in a cell, the source said, and Epstein initially had a cellmate in the special housing unit. But that person was removed for unknown reasons.
CNN previously reported that of the two officers responsible for monitoring Epstein that night, one was not currently a detention guard but was temporarily assigned to the post, per a person briefed on the matter. The guard, a man not identified by officials, had previously been trained as a corrections officer but moved to another position.
In their statement Friday, Epstein's attorneys said they may take legal action to "view the pivotal videos -- if they exist as they should -- of the area proximate to Mr. Epstein's cell during the time period leading to his death."
Federal Bureau of Prisons rules allow people who work in other prison jobs, such as teachers or cooks, to be trained to fill in at posts normally held by regular guards.
Both guards were working overtime shifts but it's unclear whether that was mandatory. One person familiar with the matter said both employees had volunteered. Union officials say the overtime was mandatory.
The two guards aren't talking to investigators and have hired lawyers, people briefed on the matter have told CNN.