The Biden administration has sent a Saudi detainee who planned to hijack planes on Sept. 11, 2001, home from Guantanamo Bay.

Mohammed al-Qahtani, who has been held at the U.S. base since 2002, was returned to Saudi Arabia for psychiatric treatment, the Pentagon announced on Monday. The Biden administration decided in February to repatriate him through a Saudi “custodial rehabilitation and mental health care program for extremists,” according to the New York Times.

The news comes as the Biden administration is reportedly considering a trip to Saudi Arabia to discuss increased oil exports. During his campaign, Biden promised to make the Gulf nation a “pariah” for killing former Washington Post journalist Jamal Khashoggi.