Kentucky State police Master Trooper Norman Chaffins told reporters officer Jason Ellis, 33, was slain about 2 a.m. Saturday while picking up debris intentionally placed on an exit ramp of the Blue Grass Parkway.
"Someone planned this, and someone planned to shoot someone at that spot and at that time," Chaffins said.
He said Ellis, a K-9 officer and seven-year veteran of the Bardstown department, was shot multiple times with a shotgun, The (Louisville) Courier-Journal reported.
However, investigators had yet to determine if the officer was the intended target or just happened to be the one to stop and clear the debris, Chaffins said.
Police have not said what type of debris was on the roadway or what type of shotgun was used. However, they said it appeared the shooter was standing when Ellis was killed.
Ellis didn't have time to pull his revolver and his body was found by passing motorists who used his police cruiser's radio to call police. The vehicle's emergency lights were flashing. The car was not equipped with video or audio equipment.
No suspects had been identified, the newspaper said.
"We're looking at the possibility of one, possibly two or three persons involved with this," Chaffins said.