A United States federal court acquitted the alleged ringleader of the 2012 Benghazi attack against an American consulate in Libya of the most serious charges, local media reported late Tuesday.

Ahmed Abu Khatallah was charged with 18 counts ranging from murder and conspiring to provide material support to terrorists, and maliciously damaging and destroying U.S. property. He was acquitted on all but four of those charges, which included terror-related charges, according to media reports.

The Sept. 11, 2012, assault killed U.S. Ambassador to Libya Chris Stevens, State Department information management officer Sean Patrick Smith and contract security officers Tyrone Woods and Glen Doherty.

The Obama administration's handling of the deadly assault became a lightning rod for Republican criticism of Hillary Clinton, who was secretary of state at the time, through her presidential campaign.