The U.S. Fish and Wildlife Service is investigating 16 incidents of wolves being killed illegally in November and December of last year.
Two wolves were killed in northern Minnesota, eight in Wisconsin and six in Michigan.
Patrick Lund is in charge of U.S. Fish and Wildlife Service offices in Minnesota and Wisconsin. Lund says the number of wolf killings isn't unusual.
"The numbers in Minnesota and Wisconsin are fairly typical," Lund said. "We'll usually find out about a few wolves being killed right around the gun deer season in Minnesota, and between six to 10 or 11 in Wisconsin each year. The problem is that we don't know how many are being killed that we don't find out about."
Wolves are on the endangered species list in Michigan and Wisconsin. In Minnesota, they are considered threatened. The U.S. Fish and Wildlife Service is offering a reward of up to $1,000 for information leading to the arrest and conviction of those responsible.