FORT CARSON, Colo. (AP) — A weeping Army sergeant on Thursday apologized to the family of a female soldier he admitted killing, after a military panel convicted him of unpremeditated murder and sentenced him to life in prison.

Sgt. Vincinte Jackson said he doesn’t know why he killed Spc. Brandy Fonteneaux, 28, of Houston. She was found dead Jan. 8 in her barracks room, stabbed 74 times. A military panel sentenced Jackson to life in prison with the possibility of parole, though prosecutors couldn’t immediately say how many years he would serve before becoming eligible.