DOWNTOWN — A federal judge on Monday dismissed a retaliation claim brought last year by a Burbank police detective who alleged that his civil rights were violated by cops who used intimidation and harassment to keep him and witnesses from talking about misconduct investigations.

U.S. District Judge Margaret Morrow dismissed Det. Angelo Dahlia's claim against the city and five current and former Burbank police officers, ruling that Dahlia was not protected by the 1st Amendment when he came forward with allegations of physical abuse in a police interrogation room because he had an official duty to report the illegal conduct.

Morrow also ruled that Dahlia's claims could not rise to the level of having had his rights violated, and that he improperly filed complaints with the court.

The tentative ruling applies to all defendants except former Police Chief Tim Stehr, who appealed an earlier ruling on the issue to the Ninth Circuit Court of Appeals.

If the former chief dismisses his appeal, the claim against him would be sent back to district court, where it could be dismissed based on the same rationale as the other defendants.

Dahlia's attorney, Russell M. Perry, said he planned to appeal the decision to the Ninth Circuit and file the remaining claims in state court. Dahlia brought to light egregious misconduct committed by fellow officers, Perry said.

Before Dahlia reported the violations, Perry said his client was threatened and intimidated by officers in an effort to keep him silent. The department reacted by placing him on administrative leave, he said.

"The city of Burbank needs more police officers like Angelo Dahlia, who had the courage to step forward and expose the physical abuses that were occurring behind closed doors at the police station," Perry said in an e-mail Tuesday. "His conduct should be praised, not punished . . . No one should have to trade in their protection under the 1st Amendment of the U.S. Constitution in order to become a law enforcement officer in this state."

Dahlia in the lawsuit alleged that high-ranking members of the department investigating the 2007 robbery of Porto's Bakery assaulted and beat witnesses and suspects "under the color of authority," according to the lawsuit filed in November.

When Dahlia complained of brutality and witness intimidation, he was told to "stop his sniveling" and was later intimidated with a brandished gun, the lawsuit states.

He also allegedly was told to "watch your back" and "keep your head down," and was constantly monitored.

Former Lt. Omar Rodriguez, retired Lt. Jon Murphy and Sgts. Edgar Penaranda, Chris Canales and Jose Duran were all dismissed as defendants in the case.

Rodriguez's attorney, Ken Yuwiler, said the court in a nutshell ruled that Dahlia was unable to plead a viable federal claim.

Dahlia brought forward the allegations of misconduct following interviews in which he failed to recount the same series of events, attorneys for the defendants said.

"The evidence shows that Mr. Dahlia admittedly told contradictory stories, and therefore he lied," Yuwiler said.

"Credibility is important, and Mr. Dahlia doesn't have any."