SAN FRANCISCO — Lawyers for the pilot of the ship that struck the San Francisco-Oakland Bay Bridge say there is new evidence raising doubts about the Chinese crew's truthfulness after the incident, but say the crew should be detained as witnesses for several more months.

The six crew members have already been held in Northern California as "material witnesses" for eight months while the case against Capt. John Cota plods along.

Cota was at the helm of the container ship Cosco Busan last November when it sideswiped a bridge support tower, spilling 53,000 gallons of bunker fuel into the fragile bay. He is charged with two misdemeanor environmental crimes and two felony charges of lying to the U.S. Coast Guard about his medical record.

Cota's lawyers argued in court Friday that some or all of the crew members should be held at least until October to testify at Cota's scheduled trial.

Lawyers had planned to question several crew members on Monday, but a U.S. magistrate judge canceled the depositions when Cota's defense lawyers said the new evidence was too voluminous and complex for them to process in time.

Lawyers for four crew members argued strenuously for the deposition to go forward on Monday and said the "reasonable period of time" for a witness to be deposed has already "been taxed to its constitutional limits."

"Any further delay is unconscionable," the lawyers said in a court filing.

Federal prosecutors have been investigating new evidence that, according to court documents, suggests the Chinese crew altered certain unidentified records after the Cosco Busan accident.

Much of the details of the new evidence were filed under seal, and Josh Easton, a spokesman for the U.S. attorney's office in San Francisco, declined comment Friday.

But documents filed by attorneys for Cota and the crew members, and responses to those documents by prosecutors, shed some light on the evidence.

The new evidence, including "computer images" extracted from the ship's equipment, also raises doubts about the Chinese crew's competency in operating and interpreting the ship's electronic chart system and other equipment, according to documents filed by federal prosecutors on July 14.

Also, according to Cota's lawyers, the prosecution has said the Chinese captain has admitted "he did not know how to interpret the symbols on the electronic chart."

Such an admission would bolster the defense of Cota, who has said on the foggy morning of Nov. 7, the Chinese captain mistakenly guided him into the bridge support fender by misidentifying symbols on the electronic charts.

Cota has told National Transportation Safety Board investigators that in the moments leading up to the collision, he had pressed the captain, Sun Mao Cai, "three separate times" on where the bridge supports were on the ship's electronic charts. But minutes after the crash, the Chinese captain insisted to a crew member that he had given correct information to Cota, the NTSB said.

Also Friday, U.S. District Judge Susan Illston rejected Cota's request she throw out the charges against him. Cota has pleaded not guilty. But Illston did agree to split the environmental and false-statements charges, setting up two separate trials for Cota.

Illston also agreed to move the environmental-crimes trial up to Oct. 6, rather than Oct. 20 as previously scheduled.