Trooper Paul Butterfield was shot in the head during a traffic stop Monday in Mason County's Sherman Township, about 80 miles north of Grand Rapids.
Eric Knysz of Luther was charged Wednesday with murder of an officer as well as three other crimes. His wife, Sarah Knysz, 20, faces two charges related to driving away from the scene with him.
"It appears to be simply a routine traffic stop ... one that we see on the road all the time," prosecutor Paul Spaniola told reporters.
Spaniola said Eric Knysz was not wanted by authorities when Butterfield stopped the pickup truck.
"A lot of times homicides have no good reason," Spaniola said.
Sarah Knysz, who appeared in court by video camera from the county jail, won't be released unless she posts $250,000. There was no indication that either had attorneys yet.
"The circumstances arising from this matter merit a much more serious bond," Magistrate Patricia Baker said, explaining the high figure.
Eric Knysz was injured while exchanging gunfire with police as officers closed in on the couple some 15 miles from where Butterfield was shot. He's in a Traverse City hospital but was expected to appear in court Thursday. He has a criminal record that includes home invasion, a felony, in Lake County, records show.
"Good paying job trimming trees, wife that is pregnant, just moved into their own place," Knysz family friend Demo Moore told TV station WZZM. "Things were looking up. Then this happens."
Spaniola said Butterfield regularly handled cases in Mason County, especially following up with sex offenders to ensure they were complying with their many restrictions.
"He had a very soft spot for animals. He was a hard worker. He did everything by the book," the prosecutor said.
Butterfield's funeral will be held Saturday at 1 p.m. at Manistee High School. He was a trooper for 14 years.