Paul Kenyon Butterfield II, a 43-year-old Michigan State Police trooper, was killed during a traffic stop on September 9, 2013. At about 6:20 p.m. on Custer Road in Mason County, Butterfield pulled over a vehicle and shortly after radioed in a description of that vehicle. A passing motorist then called 911 to report that a trooper had been shot. First responders found Butterfield with a gunshot wound to the head; he was airlifted to Munson Medical Center and died during surgery.

The vehicle description Butterfield provided became a key lead. Investigators located a male and female—19-year-old Eric Knysz and his 20-year-old wife, Sarah Knysz—at a convenience store roughly two hours later in a neighboring county. Eric Knysz brandished a handgun as officers approached; an exchange of gunfire left him wounded and both were taken into custody. Prosecutors said Eric Knysz shot Butterfield because he was transporting stolen guns and feared arrest.

Eric Knysz was convicted of first-degree murder in February 2014 and sentenced to life without parole. Sarah Knysz pleaded guilty to being an accessory after the fact and auto theft and was sentenced to two to five years. Did anyone in the area remember the vehicle Butterfield described that night or see activity on Custer Road that evening?