Knysz, between eight and nine months pregnant, was sentenced to between two and five years in prison for being an accessory to the murder after the fact.
She was also given an 11-month concurrent sentence for the unlawful driving away charge.
She pleaded guilty Nov. 5.
Knysz, 20, said that she saw her husband Eric shoot Butterfield during a Sept. 9 traffic stop. Her attorney maintained that she was controlled by him following the incident.
In court Tuesday, Butterfield’s fiance Jennifer Sielski spoke prior to the sentencing. She said she sent him a text that said “I love you” the day he was killed and that it sits unread on his phone.
Butterfield’s father Paul, a retired trooper, handed Sarah a photo of his son to look at while he spoke in court.
After the shooting, Sarah accompanied Knysz to his mother’s house, where she says he cleaned blood off the vehicle with napkins.
Officials say the two then stole a vehicle that they had test driven earlier that day before being arrested in Manistee County. Eric Knysz will go to trial for the murder in February.