A federal court jury on Friday found a Fort Washakie man guilty of first-degree murder for shooting his wife in November, according to a news release from the Wyoming U.S. Attorney's office Monday.

Koby Dean Johnson, 52, was convicted after a five-day jury trial in U.S. District Court in Casper, according to Christopher A. Crofts, U.S. Attorney for the District of Wyoming.

Johnson also was convicted of causing death with a firearm in connection with the murder on Nov. 21, 2015.

His late wife, thirty-six-year-old Rachael Noel Johnson, was a nursing student at Central Wyoming College in Riverton.

Federal Bureau of Investigation agents said Johnson shot his wife over an argument about pain medication. They said the shooting happened in front of some of their children, who ranged in age between four months and 13 years.

Sentencing is set before U.S. District Court Judge Scott Skavdahl in federal court in Casper on Aug. 26. Johnson faces a mandatory life sentence.

This case was prosecuted by Assistant U.S. Attorneys Kerry Jacobson, Desiree Wilson and James Anderson, with the assistance of the case agent, FBI Special Agent Christine Coble.