After a three-week long investigation, the Erie County district Attorney has ruled a fatal trooper-involved shooting from last month, as justified.

“Under these facts and circumstances and the information that I have, the use of deadly force by trooper number one was legally justified,” said Erie County District Attorney Jack Daneri.  “No criminal charges will be filed against that trooper in this case."

On December 19, two state troopers went undercover and set up a deal to purchase a chainsaw from 27-year-old Keith Hawley, who posted an ad on Facebook.

The officers picked Hawley up in a van outside of a restaurant, and ended up in the parking lot of the Dollar General in Union City.

According to Daneri, that’s when Hawley pulled a gun on them.

"At that time, Mr. Hawley announced that this was a robbery, and that he wanted their money, while pointing a gun at them." said Daneri.

A struggle ensued, and according to Daneri, one of the officers jumped out of the van.

As Hawley continued to wrestle with one of the troopers, the other officer opened fire and shot Hawley three times in the torso, killing him.

"Both of them and their own actions, I feel potentially saved the life of the other person.” said PA State Police Captain Dan Hines.

Meanwhile, Robert Hull, 30, is charged with criminal conspiracy in connection to the attempted robbery of the troopers.

On Friday, Hull waived his right to a preliminary hearing.

State police say the incident shines a light on the potential dangers that troopers face, at any given moment.

"Rarely, in any other profession, is there a profession where you may be asked to take a life, save a life, or give your life, and in mere seconds, that just about occurred." said Captain Hines.

Both officers involved in the shooting have been place on administrative duties.

Their names are not being released.