U.S. Marshals pulled the sobbing mother of Jaymes Leo Whiteplume away from her son in a last embrace Thursday after he pleaded guilty in federal court to murdering a man on the Wind River Indian Reservation last year.

Whiteplume's plea concluded the federal government's prosecution of three main defendants and three accessories-after-the-fact to the brutal stabbing death of Jared Dean Little Whiteman on June 3, 2014.

In the change of plea hearing before U.S. District Court Judge Scott Skavdahl, Whiteplume recounted how he tied up Little Whiteman on a bed in a trailer, and handed a knife to Susan Chippewa who then stabbed the victim about 40 times and slashed his throat.

In exchange for the plea of felony first degree murder, Whiteplume will spend between 35 and 40 years in prison. If Whiteplume had gone to trial and was convicted, he could have faced life imprisonment.

Three other counts -- first degree murder and aid and abet, kidnapping resulting in death, and carrying a firearm during a crime of violence -- will be dismissed at his sentencing, which Skavdahl scheduled for Sept. 1.

Skavdahl has taken this and the other plea agreements in the case under advisement. He is not obligated to be bound by the agreements offered by prosecutors and defense attorneys, he said.

Last week, defendant Byron Robert Spoonhunter pleaded guilty to first degree felony murder. Felony murder is defined as a murder committed during the commission of another crime. In Spoonhunter's plea agreement, he will be sentenced to not more than 30 years imprisonment.

Skavdahl set Spoonhunter's sentencing for Aug. 25.

In April, Susan Chippewa, pleaded guilty to first degree murder aid and abet. Another charge, first degree felony murder, will be dismissed at her sentencing scheduled for July 21.

Prosecutors agreed to limit Chippewa’s sentence to 35 years imprisonment.

These defendants are enrolled members of the Northern Arapaho Tribe, as was Little Whiteman.

In March, three other people were charged, and later pleaded guilty to being accessories-after-the-fact to the crime. They are Garrett Revere Jr., Chrissy Big Eagle and Will Wallowingbull.

Their sentencings will be held in July.