Omar Abu Bakr

Omar Khalifa Mohammed Abu Bakr Mahjour Umar is a citizen of Libya who was held in extrajudicial detention in the United States' Guantanamo Bay detention camps, in Cuba, from August 5, 2002, until April 4, 2016. In 2004, the United States Supreme Court ruled, in Rasul v. Bush, that Guantanamo captives were entitled to being informed of the allegations justifying their detention, and were entitled to try to refute them.

Office for the Administrative Review of Detained Enemy Combatants Combatant Status Review Tribunals were held in a 3x5 meter trailer where the captive sat with his hands and feet shackled to a bolt in the floor.

Following the Supreme Court's ruling the Department of Defense set up the Office for the Administrative Review of Detained Enemy Combatants.

Scholars at the Brookings Institution, led by Benjamin Wittes, listed the captives still held in Guantanamo in December 2008, according to whether their detention was justified by certain common allegations:

Omar Khalifa Mohammed Abu Bakr was listed as one of the captives who "The military alleges ... are associated with Al Qaeda". The four page memo included forty "primary factors favor[ing] continued detention" and six "primary factor favor[ing] release or transfer". A repeated theme in the allegations was that Abu Bakr had attended training at multiple Afghan training camps, and that he had served as an instructor at Afghan training camps. He was also alleged to have been employed by one of Osama bin Laden's construction companies in Sudan. He was also alleged to have worn a Casio F-91W digital watch.

Second annual Administrative Review Board

A Summary of Evidence memo was prepared for annual Administrative Review Board on Omar Khalif Mohammed Abu Baker Mahjoub's second annual Administrative Review Board on October 11, 2006. The four page memo included twenty-four "primary factors favor[ing] continued detention" and two "primary factors favor[ing] release or transfer". The 2006 memo offers two versions of when his leg was injured: in Sudan in the early 1990s, and in Afghanistan in 1999. He was alleged to have met Abu Musab Al Zarqawi twice in 2000. The 2006 memo said he and the other Arab men he lived with in Pakistan had all been living together because they were seeking political asylum in Europe.

Formerly secret Joint Task Force Guantanamo assessment

On April 25, 2011, whistleblower organization WikiLeaks published formerly secret assessments drafted by Joint Task Force Guantanamo analysts. His detainee assessment written on August 22, 2008, was sixteen pages long. It was signed by camp commandant Rear Admiral David M. Thomas Jr., who recommended continued detention in Guantanamo.

2015 Periodic Review Board hearing

His Periodic Review Board was convened on June 23, 2015.

Transfer to Senegal

On April 4, 2016, Abu Bakr and another Libyan, Salem Abdul Salem Ghereby, were transferred to Senegal.