The Kentucky police department still mourning the ambush slaying of one of its officers has received a threat warning that more officers will be killed. Bardstown Police Chief Rick McCubbin said Tuesday his department received a recent letter threatening that "there are more to come." McCubbin says that was a reference to the ambush of Bardstown Officer Jason Ellis last month. The chief says the threat was turned over to Kentucky State Police and the FBI. Ellis — a K-9 officer — was hit with shotgun blasts after he got out of his cruiser to pick up tree limbs strewn on a highway exit ramp in Nelson County. McCubbin has said he thinks Ellis was targeted in the slaying. McCubbin says Bardstown police officers won't retreat from doing their job.