Kentucky authorities have few clues in the case of a cop killed in an ambush Saturday on a state highway exit ramp, but they have all but ruled out the possibility that children might have been responsible for the calculated killing of K-9 Officer Jason Ellis of the Bardstown Police Department.

A pile of debris was strewn along the ramp of Exit 34 on the Blue Grass Parkway in Nelson County, Ky., when Ellis, 33, got out of his police cruise. Then, before the officer could even pull out his gun, he was shot and killed. Investigators said the debris was intentionally placed in the area to lure someone out of their car, but there’s no evidence so far that the trap was intended to set up a police officer.

The Kentucky State Police, the lead agency in the investigation into the deadly ambush, is not ruling out the possibility that more than one person is responsible for the trap.

"I've been a trooper for 19 years and I've never seen anything like this, the level of planning," Trooper Norman Chaffins of the Kentucky State Police told ABCNews.com.

Rick McCubbin, chief of police for Bardstown, said he was enraged over the ambush that killed one of his cops, pointing to the deliberateness of the attack.

"It wasn't a traffic stop that went bad," he said. "It wasn't an arrest that went bad. That someone actually took the time to plan it and set it up makes it that much more, obviously hurtful, but it makes you mad."

Chaffins said investigators are still determining who set up the ambush that killed Ellis.

"We have no suspects at this time, but we don't believe kids were responsible because of how calculated the crime was," he said. "The location was obviously not picked randomly. Officer Ellis didn't even have time to remove his gun.”

Bardstown Mayor Bill Sheckles was scheduled to hold a news conference Tuesday at 5 p.m. about the ambush, according to the police department’s Facebook page. No other details were given.

The department offered this tribute of Ellis, who had a wife and two children, on the page:

“He was active in the community and quickly earned the respect of his peers. He served Bardstown with dignity and honor. He wore the uniform well and he will be missed more than mere words can express. We ask for your prayers and that you pray for his wife and two children. We cannot express our gratitude to all who have come with open arms and love while supporting us in this most troubling time,” the posting read.

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