MARTINEZ -- An arbitrator has reversed Contra Costa County's firing of a veteran prosecutor accused of raping a junior colleague at his Martinez home nearly three years ago, backing Michael Gressett's claim that the pursuit of rape charges by the District Attorney's Office was "tainted by political animosity," according to a copy of the ruling obtained by Bay Area News Group.

In a sharp rebuke of the county, arbitrator Norman Brand rejected six causes for dismissing Gressett, 54, including the rape allegation. Brand ordered the county to reinstate Gressett with full back-pay and benefits. He earned $140,000 in annual salary before his firing in July 2009.

Whether Gressett ever returns to work as a county prosecutor is doubtful. He remains the subject of a 13-count criminal indictment accusing him of raping the former colleague at his Martinez condominium in May 2008, using an ice pick and a handgun. Gressett, who worked in the sex crimes unit, argues that the sex was consensual. He pleaded not guilty in October.

He will likely be placed on paid administrative leave, said Mark Harrison, an investigator working for Gressett.

"He will immediately be placed back on the payroll. He'll be put on the books today," Harrison said.

County Supervisor John Gioia said he could only confirm that the arbitrator reached a decision, but offered no details. Newly elected District Attorney Mark Peterson, Gressett's friend and former supervisor, did not return a call Tuesday morning seeking comment.

County Counsel Sharon Anderson declined to comment.

The former colleague who lodged the rape allegations, known as "Jane Doe" in court papers, refused to testify during a 10-day hearing in the fall over Gressett's termination, according to Brand's 26-page ruling, dated Monday.

Her refusal "casts doubt on the credibility of the witness's prior statements," Brand wrote, describing "significant discrepancies" in statements Jane Doe made to investigators and friends, and with medical records that did not support the descriptions of trauma she told to a police detective.

"The stories Jane Doe told to different people are significantly inconsistent, they conflict with direct testimony and they are not supported by the documentary evidence," he added. "Moreover, Jane Doe had -- as the DA knew -- strong motivation to lie."

Doe, then a young prosecutor under a three-year contract, quietly settled with the county for $450,000 in 2009 -- a deal that only recently came to light. She had filed a complaint with the state Department of Fair Employment and Housing, claiming leaders in the District Attorney's Office failed for months to follow up on her allegation, leaving her "having to work in the same areas as Gressett." She also claimed the office denied her a permanent position in retaliation for the rape allegation.

Gressett's defenders have argued that Jane Doe knew when she made the rape allegations that she lagged behind in her class of young contract prosecutors and was unlikely to earn a permanent job. Brand cited a text message Doe sent to a colleague after looking at practice exam questions for a permanent job: "Just have this terrible feeling im going to end up w/no job in 3 months -- waiting tables -- exactly where I started."

In his ruling, Brand noted that the county withheld the settlement during Gressett's administrative hearing, despite a request by Gressett's side for any "consideration" the district attorney had provided her.

The arbitrator suggested political and financial motives for the District Attorney's Office to wait nearly five months before referring the rape allegation to police and placing Gressett, a three-time candidate for district attorney, on administrative leave upon his arrest in September 2008.

Former District Attorney Robert Kochly "could have required her to make a statement, but he did not. According to (chief assistant district attorney Brian) Baker, they did nothing for months because they were 'still hoping to get a cooperative statement from her.' "

"That was not their only motive," Brand wrote. "The unofficial allegation of rape left the DA's office worried about getting sued by Jane Doe if they failed to hire her as a permanent DA." Kochly also feared political consequences, Brand wrote, citing testimony from Kochly.

"I was certainly cognizant of the other implications in the matter. Mr. Gressett having, you know, run for political office, including running against me in 2002," Kochly testified.

Brand wrote that the evidence supports Gressett's contention that the office's "pursuit of these charges was tainted by political animosity because he had run for DA and currently supported Mr. Peterson against (Dan) O'Malley." Kochly and others in the office endorsed O'Malley, a former prosecutor and judge who is now a defense attorney.

The criminal case against Gressett is a separate process, but Harrison said the arbitrator's ruling validates Gressett's defense.

"From Day 1, Michael has been very clear on his innocence," Harrison said. "In our position, it was not only a politically motivated investigation, it's a financial motivation on behalf of (Doe)." He also chided the county for failing to report its settlement with Jane Doe, which a state deputy attorney general prosecuting the criminal case against Gressett said he only learned about last week.

In three of the other causes, the county relied on a statement from a woman, Jessie DeGuzman, who said Gressett gave inappropriate advice and an overly lenient deal to a former associate of hers several years ago. She also told investigators that Gressett twice paid her for oral sex.

DeGuzman's statement came with an unusual deal for the release of her "significant other" from jail -- a deal brokered by O'Malley's law partner. She later recanted the oral sex claim, and the county declined to have her testify at the hearing.

"The fact is, Ms. DeGuzman lied to help her boyfriend," wrote Brand. "When she discovered Mr. O'Malley's partner, (Tom) O'Connor, was interested in getting negative information about (Gressett), she made up her sex story. The DA's office was willing to trade."

Brand found the claims related to DeGuzman's statement "not, on its face, believable."

The other causes for firing Gressett were a claim he violated professional standards by bluntly describing crimes against a rape victim to colleagues in her presence; and seven grams of marijuana found at his home during an investigation into the rape allegations. Brand rejected the former cause as baseless, and the marijuana charge as no cause for firing.

Staff writer Lisa Vorderbrueggen contributed to this report.