A former Army officer and Detroit native who reported in 2005 that military prisoners in the Middle East were being beaten and abused by U.S. soldiers has died.

Maj. Ian Fishback of Newberry, Michigan, died suddenly Nov. 19, according to his obituary from the Beaulieu Funeral Home in Newberry. He was 42. No cause of death was listed.

Fishback’s family says he died in an adult foster care facility in Michigan, The New York Times reported Tuesday.

Fishback wrote about the abuses in a letter to top aides of Sen. John McCain of Arizona and Sen. John W. Warner of Virginia, according to the newspaper.

McCain and Warner were senior Republicans on the Senate Armed Services Committee. Warner was the committee’s chair.

Fishback and two other former members of the 82nd Airborne Division reported that prisoners in Afghanistan and Iraq were assaulted, exposed to extreme temperatures, stacked in human pyramids and deprived of sleep in an effort to extract intelligence from them, or just to amuse the soldiers, The Times reported.

Fishback also said Army superiors ignored his complaints.

“Despite my efforts, I have been unable to get clear, consistent answers from my leadership about what constitutes lawful and humane treatment of detainees,” Fishback wrote in the letter to McCain. “I am certain that this confusion contributed to a wide range of abuses including death threats, beatings, broken bones, murder, exposure to elements, extreme forced physical exertion, hostage-taking, stripping, sleep deprivation and degrading treatment. I and troops under my command witnessed some of these abuses in both Afghanistan and Iraq.”

The allegations of abuse eventually led the U.S. Senate to approve anti-torture legislation in 2005.

Fishback’s family said in a statement on the funeral home’s website that the community had supported him “through his recent difficult times.”

“He faced many challenges and many of us felt helpless,” the family wrote. “We tried to get him the help he needed. It appears the system failed him utterly and tragically. There are many questions surrounding his death and the official cause of death is unknown at this time. We can assure you that we will get to the bottom of this. We will seek justice for Ian, because justice is what mattered most to him.”

The Associated Press left a message Wednesday seeking further comment from the family.

Fishback was named by TIME magazine as one of the 100 most influential people in the world in 2006 after sending his letter to McCain.

Friends and family were scheduled to gather at 1 p.m. Saturday to honor Fishback’s life at American Legion Post #74 in Newberry. The U.S. Army Honor Guard will conclude the services, according to his obituary.

Newberry is in Michigan’s Upper Peninsula.