Jeffrey Epstein's death has been ruled a suicide by hanging, the medical examiner's office said Friday.

The determination capped days of speculation and conspiracy theories after the wealthy financier and accused sex trafficker was found unresponsive in his federal jail cell in lower Manhattan last Saturday.

The ruling wasn't unexpected: multiple law enforcement officials had previously told NBC News that Epstein's death was presumed to be a suicide.

The medical examiner's office completed an autopsy on Sunday but indicated it was waiting for more information from investigators before releasing its final determination. The autopsy revealed that Epstein had broken a bone in his neck, a source told NBC News Thursday, an injury that can occur in a suicide by hanging.

The death sparked harsh criticism of the federal prison system and led former wardens and U.S. lawmakers to question how a high-profile inmate could get the opportunity to take his own life, especially after carrying out what was believed to be a previous attempt.

"We are not satisfied with the conclusions of the medical examiner's office," Epstein's attorneys said Friday in a statement. "We will have a more complete response in the coming days."

Epstein, 66, was locked up in a special housing unit at the Metropolitan Correctional Center where he was supposed to be checked by guards every 30 minutes.

But a period of hours passed before correctional officers looked in on his cell, and investigators were probing whether they had fallen asleep, multiple officials have told NBC News.

The Justice Department, which oversees the federal prison system, took swift action. The facility's warden was ordered reassigned and the two guards tasked with watching Epstein were placed on leave in the days after the incident.

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Attorney General William Barr has said there were "serious irregularities" at the federal jail and insisted investigators "will get to the bottom of what happened and there will be accountability."

"His safety was the responsibility of the MCC. It is indisputable that the authorities violated their own protocols," Epstein's attorneys, Martin G Weinberg, Reid Weingarten and Michael Miller, said in their statement. "The defense team fully intends to conduct its own independent and complete investigation into the circumstances and cause of Mr. Epstein’s death ..."

They added that they would take legal action if necessary to view prison security videos.

Epstein was arrested July 6 on sex trafficking and conspiracy charges. Prosecutors say he sexually abused dozens of underage girls at his homes in New York and Florida in the early 2000s. Epstein was also accused of paying his victims to recruit others, allowing him to build a vast network of girls to exploit.

His lawyers asked a judge to allow him to await trial under house arrest at his Manhattan mansion, but the request was denied.

Less than three weeks before his death, Epstein was found unresponsive in his cell, with marks around his neck, in what authorities were investigating as a suicide attempt.

He was placed under suicide watch in a special cell with near round-the-clock observation. But he was removed less than a week later and returned to the special housing unit, where he was held alone in his cell and apparently left unchecked for hours.