COLORADO SPRINGS, Colo. — Spc. Darius Jennings had told his mother he was ready to return to the United States.

“About two weeks ago, he called me and he said, ‘Mama, I’m ready to come home,”’ Harriet Johnson, of Cordova, S.C., said on Monday.

Jennings was one of four soldiers based at Fort Carson to die in the crash of a helicopter in Iraq on Sunday. He had often started his sentences with, “Mama, when I get home...,” she said.

But in the more recent call, he was plain.

“He said, ‘I’m tired, I’m not used to this,”’ she said. She told him to talk to a chaplain.

Jennings, who would have turned 23 on Nov. 13, was with the 2nd Squadron of the 3rd Armored...