Gunn, 50, was listed in an FBI probe into misconduct by the Burbank Police Department, the Burbank Leader reported.
Gunn's widow Tina Gunn told the Los Angeles Times, in a story posted on its Web site today, that the department's leaders and union failed to support him against use-of-force allegations, effectively ruining his career and leaving him "brokenhearted."
"They had everything to do with what happened," Tina Gunn told The Times. "My husband felt that no matter what he did, he was going to be the fall guy because he was the one who spoke out.
"He took (the allegations) very hard. They were trying to portray my husband as something he was not. He was a good man. He was beyond clean. The department turned its back on him."
Along with the FBI investigation, two other probes are being conducted into the department, City Attorney Dennis Barlow told The Times. Barlow said he would examine their results when they become available.
Gunn's brother, Chris Topolovich, said Tuesday night he committed suicide "to shine a bright light on a problem in Burbank."
"He gave up his family to shine a bright light on a big problem in Burbank and nobody would listen," Topolovich, a former Burbank police officer, said outside Burbank City Hall.
At Tuesday night's City Council meeting, City Councilman David Gordon requested that Police Chief Tim Stehr be placed on administrative leave, saying "we have a city that's been traumatized," but none of his four colleagues supported the request.
Gunn was a 22-year-veteran and patrol sergeant with the Burbank Police Department, Dilibert said. He received numerous commendations for his work, including the Ministerial Officer of the Year in 1992, and two departmental Professional Esteem awards.