Military investigators have concluded that five U.S. service members were involved in the incineration of a pile of Korans in Afghanistan last week, according to U.S. military officials who have been briefed on the inquiry.

The burning of the Muslim holy books — which U.S. officials say was accidental — incited a week of protests that left 30 Afghans dead. The burnings also were cited as motivation for at least some of the six fatal attacks on U.S. military personnel that have occurred in Afghanistan in the past eight days.