I firmly believe that most law enforcement officers pursue their line of work out of a sincere desire to act as a deterrent and crime-solving force to protect communities from the human predators among us.

There are those, however, who join law enforcement as an easy way to acquire power and authority, which they then abuse. Jack Edmundson was this kind of cop, nothing more than a criminal with a badge.

Edmundson’s law enforcement career finally ended in 1995 when he was convicted of stealing rare coins from a drug dealer. His criminal ways didn’t end, however, and he was caught on video murdering a gun shop owner that he was extorting while posing as an undercover cop.

The fatal shooting of a western Pennsylvania gun shop owner in his business was captured on surveillance video and occurred after the suspect extorted more than $130,000 from the victim by pretending to be an undercover police officer, according to a criminal complaint.

Jack Edmundson Jr., 43, is charged with criminal homicide, attempted arson and aggravated assault in the shooting of 62-year-old Frank Petro on Tuesday inside Petro’s business, Frank’s Gun & Taxidermy Shop. Edmundson is from Saltsburg, a tiny borough next to Conemaugh Township, where Petro’s shop was located, about 35 miles northeast of Pittsburgh.

Surveillance video shows Edmundson grabbing a pistol from a display case at Petro’s shop and shooting him twice on Tuesday afternoon, according to the criminal complaint. The video also shows Edmundson pouring some kind of black powder around the shop and spraying a fuel, with which police believe Edmundson intended to set fire to the business, the complaint said.

Instead, Petro — who survived the initial shooting — got up and scuffled with Edmundson and shot him in the thigh before Edmundson shot Petro at least one more time in the face, police allege, citing the video.

While it was stupid for Petro to involve himself in an underground lottery, it certainly wasn’t a felony offense and he should have gone to the real authorities the moment that Edmundson tried to shake him down.

Update: At some point after spending time in prison, Edmunson worked as an confidential informant for the police, though he had since been “deactivated.”