Guilty plea set in planned attack on San Francisco Pier 39

A man who allegedly planned a Christmas Day bombing and shooting attack at San Francisco's Pier 39 is set to plead guilty in a federal case, though details weren't public Monday.

Court records show Everitt Aaron Jameson will enter a plea June 4 in federal court in Fresno.

It's unclear what he'll plead to because Lauren Horwood, a spokeswoman for the U.S. Attorney's Office, said details of the plea agreement are not yet public.

The former Modesto tow-truck driver had pleaded not guilty in January to charges of attempting to aid a terrorist organization and distributing bomb-making information. Each carries a maximum penalty of 20 years in prison.

The FBI arrested Jameson on Dec. 22 after he talked to undercover agents, including one he thought was with the Islamic State group. The FBI says he told agents that he planned to use pipe bombs to channel victims into part of the popular tourist destination so he could shoot them.

Court documents say he told agents how to build pipe bombs and where he intended to assemble the bombs, and asked undercover agents for remote timers.

Jameson's federal defenders did not immediately return telephone and email messages.

Assistant federal defender Charles Lee previously said investigators found no bomb-making materials and his client had expressed second-thoughts. He said that two rifles and a handgun found during a search were legally owned by a relative and were locked in a gun case where Jameson couldn't to get them.

A federal magistrate earlier found that Jameson has a history relating to drug abuse and appears to have a mental health condition.