A tow truck driver in California was arrested on Friday and charged with attempting to provide support to terrorists by plotting to attack people, possibly with explosives, at a crowded pier in San Francisco before Christmas.Everitt Aaron Jameson, 26, a former member of the US Marine Corps, told an undercover investigator with the FBI he wanted to mount the attack to show support for militant group Islamic State, according to court papers.When investigators searched Jameson's home in Modesto, less than 100 miles (161 km) east of San Francisco, they found several firearms - including a Winchester rifle and a handgun - and fireworks, according to the court papers.They also found a last will and testament that said "long live" Islamic State.Jameson, in conversations with the undercover FBI investigator whom he mistakenly believed to be associated with Islamic State, is accused of outlining a plan to use explosives at Pier 39 in San Francisco, a complex with stores, restaurants and an aquarium. He hoped to force people to flee into one location where he would attack them, court papers said.He expressed interest in mounting a suicide attack between Dec. 18 and Christmas Day and asked the undercover investigator for an assault rifle and materials for rudimentary explosives, the court papers said."Today, our incredible law enforcement officers have once again helped thwart an alleged plot to kill Americans," US Attorney General Jeff Sessions said in a statement.A spokeswoman for the Federal Bureau of Investigation said in an email that, following Jameson's arrest, there was "no specific and credible threat" to the San Francisco Bay Area.Jameson was charged in a one-page criminal complaint filed in federal court with attempting to provide material support to a foreign terrorist organization.If convicted, Jameson could face a sentence of up to 20 years in prison. He was scheduled to appear in US court in Fresno, California, on Friday afternoon.In a mistake in the investigation, an FBI employee on Monday using a telephone line with a Washington, D.C., area code mistakenly called Jameson's cell phone and hung up when he answered, court documents said. Jameson called the number back and got the voicemail for the employee, who did not identify as working for the FBI.Jameson later, in conversations with the undercover investigator, expressed reservations about the plot, the affidavit said.An attorney for Jameson could not immediately be reached for comment.Jameson told an FBI informant in October that he professed faith in Islam two years earlier at a Muslim center.