Homicide

Colorado man seeks to avoid prison in murder of teacher in Bakken oil patch; sentencing Friday

  • FILE - In this Tuesday, Feb. 14, 2012 file photo, Michael Keith Spell, appears at a hearing in the Williams County Courthouse in Williston N.D. Spell is scheduled to be sentenced Friday, April 17, 2015, convicted of the murder of a Montana teacher whose death highlighted the downsides of an oil boom that’s brought thousands of newcomers to the Northern Plains. Prosecutors are recommending 100 years in prison for Spell, 25, of Parachute, Colo., in the 2012 killing of Sherry Arnold. Defense attorneys want Spell sentenced to an institution for the mentally disabled.(AP Photo/Elijah Nouvelage, File)

    FILE - In this Tuesday, Feb. 14, 2012 file photo, Michael Keith Spell, appears at a hearing in the Williams County Courthouse in Williston N.D. Spell is scheduled to be sentenced Friday, April 17, 2015, convicted of the murder of a Montana teacher whose death highlighted the downsides of an oil boom that’s brought thousands of newcomers to the Northern Plains. Prosecutors are recommending 100 years in prison for Spell, 25, of Parachute, Colo., in the 2012 killing of Sherry Arnold. Defense attorneys want Spell sentenced to an institution for the mentally disabled.(AP Photo/Elijah Nouvelage, File)  (The Associated Press)

  • FILE - In this Nov. 5, 2013 file photo, Rhonda Whited-Rupp holds a picture of her sister, Sherry Arnold, seen in a cowboy hat, and Arnold’s family in Sidney, Mont. Michael Keith Spell is scheduled to be sentenced Friday, April 17, 2015, convicted of the murder of Arnold, a Montana teacher whose death highlighted the downsides of an oil boom that’s brought thousands of newcomers to the Northern Plains. Prosecutors are recommending 100 years in prison for Spell, 25, of Parachute, Colo., in the 2012 killing. Defense attorneys want Spell sentenced to an institution for the mentally disabled.(AP Photo/Matthew Brown, File)

    FILE - In this Nov. 5, 2013 file photo, Rhonda Whited-Rupp holds a picture of her sister, Sherry Arnold, seen in a cowboy hat, and Arnold’s family in Sidney, Mont. Michael Keith Spell is scheduled to be sentenced Friday, April 17, 2015, convicted of the murder of Arnold, a Montana teacher whose death highlighted the downsides of an oil boom that’s brought thousands of newcomers to the Northern Plains. Prosecutors are recommending 100 years in prison for Spell, 25, of Parachute, Colo., in the 2012 killing. Defense attorneys want Spell sentenced to an institution for the mentally disabled.(AP Photo/Matthew Brown, File)  (The Associated Press)

  • Michael Keith Spell, 25, sits in state District Court in Sidney, Mont., Friday, April 17, 2015.  He awaits sentencing for the 2012 murder of a 43-year-old local teacher in the booming Bakken oil patch of Montana and North Dakota. Spell, who is mentally disabled, pleaded guilty to killing teacher Sherry Arnold when he attempted to abduct her as she was jogging. (AP Photo/Matthew Brown)

    Michael Keith Spell, 25, sits in state District Court in Sidney, Mont., Friday, April 17, 2015. He awaits sentencing for the 2012 murder of a 43-year-old local teacher in the booming Bakken oil patch of Montana and North Dakota. Spell, who is mentally disabled, pleaded guilty to killing teacher Sherry Arnold when he attempted to abduct her as she was jogging. (AP Photo/Matthew Brown)  (The Associated Press)

A Colorado man is scheduled to be sentenced Friday for the murder of a Montana teacher whose death highlighted the downsides of an oil boom that has brought thousands of newcomers to the remote Northern Plains.

Prosecutors have recommended 100 years in prison for 25-year-old Michael Keith Spell of Parachute, Colorado, for the 2012 killing of Sherry Arnold.

Defense attorneys want Spell sentenced to an institution for the mentally disabled. They say co-defendant Lester Van Waters threatened to kill Spell unless he went along with Waters' plan to kidnap a woman.

The body of Arnold, a popular 43-year-old math teacher at Sidney High School, was found in a shallow grave near Williston, North Dakota, months after her disappearance.

Spell and Waters had come to the region to work in the Bakken oil patch.