Investigators say the alleged thrill-killing of as many 600 animals in Columbia and Marquette counties is the worst case in the nation this year.

The Humane Society of the United States recently contacted authorities involved in investigating and prosecuting Josh Kerl and Adam Stalsberg.

The men are accused of using a high-powered rifle and spotlight to shoot animals from their vehicle over the past year.

The organization wants meaningful fines, permanent revocation of hunting licenses and restitution for the deaths of protected animals.

Kerl and Stalsberg are accused of killing mostly small game out of season, including hundreds of rabbits, squirrels and raccoons.