Officials at the U.S. Penitentiary in Leavenworth are awaiting autopsy results to learn what killed an inmate over the weekend, a prison spokesman said.

Officials at the U.S. Penitentiary in Leavenworth are awaiting autopsy results to learn what killed an inmate over the weekend, a prison spokesman said.

Inmate Benjamin Johnson, 35, was found to be unresponsive at about 3 p.m. Saturday at the federal prison.

Staff began performing life-saving measures, and Johnson was transported to a local hospital. But he subsequently died, according to USP spokesman Sean Janson.

Johnson had been at the USP since Feb. 4, 2015. He was sentenced in Kansas to 81 months for conspiracy to possess marijuana with the intent to distribute.

Johnson was housed at the main prison on the USP grounds, which is a medium security facility.

Janson said Johnson’s death was unrelated to the case of an inmate who walked away Friday from the minimum security Federal Prison Camp located on the USP grounds.

That inmate, Timothy Taylor, later turned himself in at the camp.