Adam Dandach was also charged in the superseding indictment with obstructing justice by trying to destroy records of his online activity to thwart investigators.
Dandach was stopped in July in the Orange County airport while trying to board a flight to Turkey with an expedited replacement passport he got after he said he accidentally threw his old one away. Prosecutors said he knew that wasn't true and that his mother had confiscated the passport when she heard about his plan to go overseas.
When told he could face criminal charges, Dandach said he was more disappointed about not going to Syria than about getting in trouble with the law, according to court papers.
Dandach is in custody and scheduled to be arraigned March 16 on the new charges.
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"He's going to plead not guilty and we're going to fight them in court," defense lawyer Pal Lengyel-Leahu said.
If convicted, Dandach could face up to 15 years in federal prison on the terrorism charge, and up to 25 years on each of the other counts, federal authorities said.