WASHINGTON (AP) — In its final hours, the Obama administration on Thursday released the last of three installments of documents belonging to Osama bin Laden that were seized in a 2011 raid that killed the al-Qaida leader in his secret compound.

Tracking down and killing the man behind the 2001 terrorist attacks on America is one of President Barack Obama's greatest accomplishments.

Intelligence officials have been working for more than two years to declassify the hundreds of documents captured in the raid. The last batch consisting of 49 documents include letters to and from bin Laden, his deputies and his mother. The documents also include a running disagreement between bin Laden and al-Qaida's affiliate in Iraq, which morphed into the Islamic State group. Those militants are currently the top target of U.S. counterterrorism efforts.

The Pentagon announced Thursday that the U.S. Air Force attacked a pair of IS military camps in Libya, seeking to eliminate extremists who had escaped the former IS stronghold of Sirte

Bin Laden is responsible for orchestrating the 2001 terrorist attacks on the U.S. that killed nearly 3,000 people. The attacks drastically changed America's footprint abroad and challenged some of the most basic tenets of the U.S. Constitution in an effort to detect terrorists before they strike.