Digital Vision, ThinkStock

KTVB - A Fort Hall man was sentenced Wednesday to two years and three months in federal prison for shaking a 10-month-old girl to death last year. 

Ian Jack Crooked Arm, 27, has already spent nine months in the tribal jail on the Fort Hall Indian Reservation.

Prosecutors say the baby's mother left her with Crooked Arm to go to work on Feb. 20, 2013. He called her ten minutes later, saying something was wrong. The mother returned to the house, where Crooked Arm said the girl was "breathing funny." The mother attempted CPR and called 911, but despite being air-lifted to Primary Children’s Medical Center in Salt Lake City, the baby died.

Crooked Arm was charged after an autopsy three days later revealed the girl died from abusive head trauma. The suspect admitted to his mother during a recorded jailhouse phone call that he had shaken the baby "too hard." He later pleaded guilty to involuntary manslaughter.

At the sentencing, Chief U.S. District Judge B. Lynn Winmill also ordered Crooked Arm to undergo three years of supervised release after his release.