Two new autopsy reports on the body of an Aboriginal man who died while in a Darwin jail 20 years ago say there is no evidence lesions on his body were caused before death.

A coronial inquest and the Royal Commission into Aboriginal Deaths in Custody in 1991 found Douglas Bruce Scott hanged himself in the Berrimah jail, but his wife Letty Scott believes her husband was killed by four prison guards.

Mr Scott's body was exhumed in Townsville in north Queensland this month and new autopsies conducted.

One of three reports completed by forensic experts challenges the original inquest findings, saying lesions on Mr Scott's body were consistent with torture procedures.

The first autopsy report by a forensic specialist, Brazilian physician Jorge Paulete Vanrell who was engaged by Mrs Scott, challenges the original inquest findings.

The report found lesions that were "consistent with torture procedures", like being kicked in the genital region, and fractures "usually produced by hand strangulation".

"All lesions present were not inflicted by the victim himself," the report said.

Dr Vanrell is a professor of forensic medicine and criminology at the Police Academy of Sao Paulo in Brasil.

But the two remaining reports suggest otherwise.

One report by a Queensland pathologist says there was no evidence of suspicious trauma before death.

The final report by a specialist engaged by the Northern Territory Government says it is impossible to confirm whether damage to Mr Scott's body occurred before or after his death.