CADMAN PLAZA EAST (AP) — A New Yorker who became a sworn member of al-Qaida has begun testifying at a terrorism trial in Brooklyn.

Bryant Neal Vinas testified yesterday at the federal trial of Adis Madunjanin, who is charged with plotting to attack Manhattan subways in 2009. Medunjanin denies the charges.

Vinas testified that he went to Pakistan in 2007 and was able to participate in an attack against U.S. forces in Afghanistan within two weeks. Months later, he joined al-Qaida.

Vinas, a native of Patchogue on Long Island, previously pleaded guilty to terrorism charges in Brooklyn. He’s become a key government cooperator.