Federal investigators are still examining Donald Trump’s role in inciting the attack on the US Capitol.

Michael Sherwin, the departing acting US attorney for the District of Columbia, confirmed that the former president is still under investigation over the 6 January putsch in an interview with CBS 60 Minutes on Sunday.

“Maybe the president is culpable,” he said.

Sherwin also said there were now more than 400 cases against participants in the riot and said that if it is determined Brian Sicknick, the Capitol police officer who died, did so because he was hit with bear spray, murder charges would likely follow.

“It’s unequivocal that Trump was the magnet that brought the people to DC on 6 January,” Sherwin said. “Now the question is, is he criminally culpable for everything that happened during the siege, during the breach?

“…Based upon what we see in the public record and what we see in public statements in court, we have plenty of people – we have soccer moms from Ohio that were arrested saying, ‘Well, I did this because my president said I had to take back our house.’ That moves the needle towards that direction. Maybe the president is culpable for those actions.

“But also, you see in the public record, too, militia members saying, ‘You know what? We did this because Trump just talks a big game. He’s just all talk. We did what he wouldn’t do.’”

Trump addressed a rally outside the White House on 6 January, telling supporters to “fight like hell” to stop Congress certifying his election defeat by Joe Biden, which he falsely claims was the result of voter fraud. A mob broke into the Capitol, leading to five deaths, including a Trump supporter shot by law enforcement.

Trump was impeached for inciting an insurrection but acquitted when only seven Republican senators could be convinced to vote him guilty.

Lawsuits over the insurrection, one brought by the Democratic congressman Bennie Thompson under the Ku Klux Klan Act of 1871, are among proliferating legal threats to Trump now he has lost the protections of office.

More than 100 police officers were allegedly assaulted during the riot. Sicknick died the next day. Cause of death has not been released. But two men have been charged with assaulting the 42-year-old officer with a spray meant to repel bears.

Asked if a determination that Sicknick’s death was a direct result of being attacked with the spray would lead to murder charges, Sherwin said: “If evidence directly relates that chemical to his death, yeah. We have causation, we have a link. Yes. In that scenario, correct, that’s a murder case.”

He also said: “That day, as bad as it was, could have been a lot worse. It’s actually amazing more people weren’t killed. We found ammunition in [one] vehicle. And also, in the bed of the vehicle were found 11 Molotov cocktails. They were filled with gasoline and Styrofoam. [Lonnie Coffman, the man charged] put Styrofoam in those, according to the [Bureau of Alcohol, Tobacco, Firearms and Explosives], because when you throw those, when they explode, the Styrofoam will stick to you and act like napalm.”

He also said pipe bombs placed near the Capitol by an unidentified suspect were not armed properly.

“They were not hoax devices, they were real devices,” Sherwin said.

Sherwin also said sedition charges, as yet not part of cases against participants in the riot, were likely.

“We tried to move quickly to ensure that there is trust in the rule of law,” he said. “You are gonna be charged based upon your conduct and your conduct only.

“…The world looks to us for the rule of law and order and democracy. And that was shattered, I think, on that day. And we have to build ourselves up again. The only way to build ourselves up again is the equal application of the law, to show the rule of law is gonna treat these people fairly under the law.”