11:15 a.m.SAN FRANCISCO — The attorney for the former BART police officer from Napa who is accused of murdering an unarmed man on New Year’s Day asked for the district attorney to be removed from the case.

In court documents filed Tuesday, attorney Michael Rains asked an Alameda County Superior Court judge to disqualify District Attorney Tom Orloff from Johannes Mehserle’s murder case.

Rains argues that Orloff deliberately violated Mehserle’s right to remain silent when police tried questioning Mehserle without a lawyer after being arrested on Jan. 13 in Nevada.

Mehserle — a 2000 graduate of New Technology High School in Napa and a 2006 graduate of the Napa Valley College Police Academy — has pleaded not guilty to murder and is free on $3 million bail. Rains has argued Mehserle, 27, meant to fire his Taser when he fatally shot Oscar Grant, 22, on an Oakland train platform.

Grant’s family has since filed a $50 million wrongful-death lawsuit against the transit system.

Mehserle resigned from the BART police on Jan. 7. Tension between police and the community has risen steadily since videos of shooting appeared on the Internet.

Rains said Tuesday that Orloff was under immense pressure to make an arrest and wrote in the filing that Orloff “formulated and orchestrated a systematic effort to get Mesherle to talk — and confess — without the knowledge, and outside the presence, of his lawyer.”

Orloff said Tuesday he could not respond at length because of a judge-imposed gag order, only saying, “It’s extremely frustrating to be in this position.”

The filing also includes the notes of two Oakland police officers, who said Orloff told them to question Mehserle while in Nevada. There is also a sworn statement by Christopher Miller, Mehserle’s former lawyer, that he told BART and prosecutors several times that Mehserle would not speak to investigators.

“They were hoping he would cave into the pressure under the immediate situation and without a lawyer present,” Rains said Tuesday. “I think what we have here is a very compelling account of an effort by the district attorney to deprive Mr. Mehserle of his constitutional rights.”

Mehserle has a preliminary hearing scheduled on May 18.