BATTLE CREEK, MI (WNWN) - A Calhoun County man, who was arrested for open murder after a standoff with police, has a violent criminal history dating back decades.

52-year-old Robert Curtis Nelson has been formally charged with open murder and being a habitual offender and is being held without bond.  He is charged with beating his roommate, 51-year-old John George, to death with a baseball bat at a home on Sharon Avenue in Pennfield Township.

Nelson spent 20 years in prison after he was convicted in the early 80’s of assault with intent to murder and criminal sexual conduct.

He was arrested as recently as 2010 for assaulting a police officer.  

He is being held in the Calhoun County jail.