The case against Justin Kaliebe was announced today. The 18-year-old pleaded guilty in February to providing material support to a terrorist organisation.
Authorities wouldn't say why that plea was kept secret. They say the investigation is ongoing.
A criminal complaint says that during conversations with undercover investigators Kaliebe talked about his desire to join al-Qaeda in the Arabian Peninsula so he could wage jihad, or holy war.
US agents arrested the Long Island resident in January at Kennedy Airport as he was boarding a flight to Oman.