Twenty-one Saudi Arabian military students were expelled from the United States due to ties to jihadism and child porn, the Pentagon said on Monday

The Department of Defense expelled the students following a Department of Justice investigation into a shooting perpetrated by Saudi Arabian Air Force 2nd Lt. Mohammed Alshamrani in December. Investigators discovered the students “engaged in activity that raised serious concerns, including social media containing some jihadi or anti-American content and some kind of contact with child pornography,” Pentagon press secretary Alyssa Farah said in a statement provided to the Washington Examiner.

“Upon notification of these circumstances, the Department of Defense worked with the Kingdom of Saudi Arabia to withdraw the students from training and in consultation with the Department of Justice, the DOD worked with the Saudi Embassy in the United States to return these students to Saudi Arabia,” she added.

Following the shooting, Secretary of Defense Mark Esper ordered a review of the vetting procedures of the Pentagon’s foreign military training program, which has hosted 1 million foreign troops since 2000, Pentagon spokesman Lt. Col. Uriah Orland told the Washington Examiner.