Authorities are investigating whether the killing of a 65-year-old man is connected with two other shootings in northern Colorado.

A man was found lying on a sidewalk bleeding from gunshot wounds Wednesday night in Loveland, about 50 miles north of Denver. Police say they were unable to save him.

About 15 miles away, a bicyclist was shot to death in the city of Windsor on May 18, and a woman driving on nearby Interstate 25 was shot in the neck April 22 but survived. Police have connected those two cases, but have not said how.

There also have been a string of broken vehicle windows reported by drivers in northern Colorado since the I-25 shooting. But investigators so far have not found proof of gunshots in those cases.