Lawyers for accused Chelsea bomber Ahmad Khan Rahimi urged a federal judge on Tuesday to limit testimony about his alleged terrorist motives and keep the government from calling an expert to testify about Osama bin Laden and ISIS at the New Jersey man’s scheduled October trial.

“The government wants to now add on to the indictment this gloss of terrorism,” defense lawyer Sabrina Shroff told U.S. District Judge Richard Berman in Manhattan. “They want to inject that into a case that is already volatile enough.”

Rahimi, 29, of Elizabeth, New Jersey, is accused of planting two pressure-cooker bombs in Chelsea last Sept. 17, one of which exploded and injured 30 people. He is also accused in New Jersey of planting bombs there, and starting a shootout with police when he was captured.

He is charged with using a weapon of mass destruction and explosives, and property-destruction crimes, but not terrorism or aiding a terrorist group.

Prosecutors say they are entitled to show his motive and want an expert to testify about a journal in which Rahimi praised bin Laden and other terror groups and figures.

Prosecutor Shawn Crowley said the journal entry referencing bin Laden was a “letter” to the government.

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“It’s the defendant’s claim of responsibility,” she said. “It’s the defendant telling the government what he did and why he did it.”

Shroff said the case should focus on to the facts of what happened last September. Expert testimony about bin Laden and others named in the journal — such as the late al-Qaida recruiter Anwar al-Awlaki and Fort Hood shooter Nidal Hasan — would be too prejudicial, she said.

“I think everyone knows who Osama bin Laden is, or was,” Shroff said. “I really don’t think we need that.”

In addition to limiting terrorism evidence, Rahimi’s lawyers want Berman to dismiss a charge of using a destructive device during a crime of violence, which carries a mandatory life sentence. They say the law doesn’t apply to a bombing with no other crime of violence.

Berman said he would announce his rulings on Thursday.