Ex-marine behind thwarted attack at San Francisco's Pier 39 sentenced to 15 years

27-year-old Everitt Aaron Jameson pleaded guilty in June after being arrested for attempting to provide material support to ISIS.

The FBI had started watching Jameson in September after finding that he "liked" or "loved" posts about terror attacks and ISIS on Facebook, according to the plea agreement.

Undercover FBI agents later posed as ISIS supporters and contacted Jameson. He met with one on December 16, and said he was well versed in the "Anarchist Cookbook," a book that includes instructions for making explosives. He also said that "we need something along the lines of New York or San Bernardino," making reference to prior terrorist attacks.

Ready to die

According to the plea agreement, he also noted that he could get PVC pipe, nails and powder for explosive devices, and asked one undercover agent for remote timing equipment, adding that Christmas Day "was the perfect day to commit the attack." He told the agents he did not have an escape plan because he was "ready to die."

"Jameson put his fellow Americans at risk by supporting ISIS and planning an attack on behalf of the terrorist organization," said Assistant Attorney General for National Security John C. Demers in a statement Monday. "This is unacceptable, and I am grateful for the hardworking agents and prosecutors who are responsible for this successful result."

Jameson served in the US Marines in 2009 and attained a sharpshooter rifle qualification, according to court papers. He was later discharged for fraudulent enlistment because he failed to disclose a latent asthma history.

When authorities searched his home in Modesto, California, they found a handwritten letter that said: "you've allowed Donald Trump to give Al Quds away to the Jews," apparently a reference to President Donald Trump's decision to recognize Jerusalem as the capital of Israel.