Omar Khalif Mohammed Abu Bakr Mahjour Umar

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

His Periodic Review Board was convened on June 23, 2015. According to the Miami Herald the officials reviewing Baker's status were told he had ties to al Qaeda from the time the organization was based in Sudan, during the early 1990s. They were told he had "probably" fought against the Northern Alliance.

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

On August 31, 2009, Corrections One, a trade journal for the prison industry, speculated that "Omar Khalifa Mohammed Abu Bakr" was one of ten captives that might be moved to a maximum security prison in Standish, Michigan.

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:

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".

Originally the Bush Presidency asserted that captives apprehended in the "war on terror" were not covered by the Geneva Conventions, and could be held indefinitely, without charge, and without an open and transparent review of the justifications for their detention. 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.

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. Abu Bakr's Guantanamo detainee ID number is 695. American intelligence analysts estimate that Abu Bakr was born in 1972 in Al Bayda [sic], Libya.