OAKLAND -- A judge has discarded some portions of a Pleasanton man's lawsuit claiming his civil rights were violated by the city, Alameda County and a string of defendants, including a county sheriff's deputy and a Pleasanton police officer.

Brian Lancaster filed the suit in U.S. District Court against Officer Tim Martens and others in 2012. In it, he claims Martens unlawfully arrested him and that Deputy Ryan Silcocks illegally gave Lancaster's ex-wife, Lisa Secord, confidential information, as part of a concerted effort to deprive Lancaster of his child custody rights. Lancaster is seeking $3 million in damages.

On March 25, U.S. District Court Judge William Alsup dismissed federal civil rights claims against the county and city because Lancaster's attorneys could not prove the alleged actions of Silcocks and Martens were part of an "official custom or policy" of the county or city, court records show.

But the judge denied a motion to dismiss a federal civil rights claim against Martens, who Lancaster alleges made a false arrest at the urging of San Ramon attorney Lesley Regina, Silcocks and Secord.

The judge has set a 90-day discovery period for Lancaster's attorneys to interview Martens and Regina, collect more data from the city and county and to try to substantiate their client's allegations.

Federal claims against Regina and the other defendants are on hold pending further discovery.

Lancaster's lawyer, Jeff Hubins, said he has to prove Regina and Martens colluded to violate Lancaster's civil rights for the rest of the defendants to remain in federal court.

"We've caught Regina and Martens in a number of inconsistencies," Hubins said. "We've got to prove a conspiracy, and that's not easy to prove ... It's going to come down to an issue of credibility."

Hubins put odds at "slimmer than great" that other defendants besides Martens would be included in any federal action and that the cases will likely move to state court.

Pleasanton City Attorney Jonathan Lowell said the judge's decision to dismiss the federal civil rights claim against the city came because it did not sufficently "allege facts in a cause of action" against the city. But regarding Martens, who remains employed by the city, Lowell said: "There are sufficient facts that have been alleged such that the matter will continue; the litigation will proceed, and the city will continue to represent Officer Martens and present a vigorous defense."

The city and county are still defendants in the lawsuit on state claims.

Lancaster said he was pleased with the judge's ruling and is hopeful for a thorough discovery of Martens' history.

"It's great," he said. "It shows that the judge sees there's a reason to go forward."

Martens, who Lancaster says is a friend of his ex-wife, arrested Lancaster in January 2012. Lancaster accuses Martens of arresting him after an unwarranted traffic stop and "planting" methamphetamine in his car.

Lancaster was charged and jailed, but all charges stemming from the traffic stop arrest were dismissed by the District Attorney's Office.

In a response filed in court Tuesday, Martens denies all allegations in the lawsuit.

"Obviously he's very concerned about the allegations that Lancaster has made against him," said Martens' attorney, Cliff Campbell. "He denies any misconduct or wrongdoing ... We don't know why Lancaster is making the allegations, but we feel these will be proven to be false."

Campbell said the traffic stop should be evaluated on its own and not included alongside the state claims, adding that he would be working on a dismissal over the next 90 days.

Silcocks has been charged in criminal court with three misdemeanor counts of improperly accessing data from a county law enforcement database (including those of Lancaster), and Regina is charged with a misdemeanor count of knowingly receiving the records. They have a superior court date on April 16.

Contact Jeremy Thomas at 925-847-2184. Follow him at Twitter.com/jet_bang.