"I want to restore my good name. My reputation has been slandered and very nearly destroyed," Longmire said. "I need the Oakland police department to recognize the wrongs they have done."
Longmire's charges against the department are listed in the lawsuit he filed on Wednesday in federal court.
Longmire was the homicide detective who led the investigation into the murder of Oakland newspaper editor Chauncey Bailey who was shot to death in downtown Oakland three years ago.
Devaughndre Broussard, a worker at Your Black Muslim bakery Confessed to the killing. The bakery's leader, Yusuf Bey, was indicted last year and charged with ordering the murder.
Some police officials suspected Longmire compromised the probe because of his ties to Bey and the bakery. He was put on paid administrative leave while internal affairs looked into it.
A state attorney general's investigation concluded that Longmire mishandled the probe by failing to look into Bey's possible ties to the murder.
Longmire said he couldn't talk about that, because of a judge's gag order, but he addressed his relationship with Bey.
"It was the same as any other member of the Oakland community. It was nothing more or nothing less," he said.
He says police officials made him a scapegoat and their investigative protocols are in his words "corrupt."
"They draw up the plays the way they want and then they execute it according to their own fancy at the cost of other good men and women and their families they affect," Longmire said.
The department eventually cleared Longmire, but he says the damage was already done.
"It's been immeasurable. I can't tell you about the nights I've lost sleep," he said. "I can't tell you how it's affected my son and how many times over the last three days he has asked me, 'dad, are you ok?'"
"If anything he should be rewarded and acknowledged for the good work he did as an investigator in this case and others," Longmire's attorney John Scott said.
Longmire returned to duty last fall after he was cleared, but the 24-year veteran officer was re-assigned from homicide to patrol.
ABC7 called the Oakland post where Chauncey bailey worked but they did not return our calls.
Oakland police say they couldn't comment on a pending lawsuit, but added that because the suit targets police officials, they'll ask outside counsel to represent them.