A handgun stolen from a Port Allen police officer, who other media sources have identified as Police Chief Esdron Brown, was used more than 900 miles away in a gas station murder six years ago, according to Oklahoma cold case detectives.

The Oklahoma State Bureau of Investigation arrested three suspects in February in relation to the 2013 slaying of 77-year-old Charles Nieman, who was getting gas in Boise City, Oklahoma, with his wife when a man pointed a gun at him and demanded his wallet, according to the OSBI's Facebook page.

Nieman, who was hearing impaired, was confused about what the assailant was asking, and the man shot him in the head and then fled on foot. The vehicle the shooter had arrived in also left the scene, according to detectives.

In a bizarre twist, the investigators, using new computer software, later matched the shell casings from the murder weapon to a then-recently stolen Port Allen Police Department handgun.

OSBI investigators did not publicly identify Brown as the officer whose weapon was stolen, but The Oklahoman and WAFB-TV both identified the chief as the theft victim. Brown did not respond to a call for comment Thursday evening.

The Glock .40-caliber handgun was issued to Brown on June 1, 2013, WAFB is reporting, and Brown filed a formal complaint about the weapon theft on July 24, 2013.

OSBI Director Ricky Adams said in a press conference on Feb. 14 of this year that investigators believe Brown’s gun was stolen from a vehicle parked outside his house in June 2013.

According to a video of the press conference, Adams said investigators reconstructed the assailants’ route — a crime spree he called “drug fueled” — from Harrison County, Mississippi, on June 6, 2013, and then four days later to Conroe, Texas, where they committed an armed robbery. Based on that information, investigators believe the assailants spent days traveling along Interstate 10, stopping in Port Allen to commit the handgun theft. Investigators did not say if the same stolen handgun was used in the Texas armed robbery, but Adams did say two of the suspects served jail time in Texas for that crime.

Adams said at the same time the police weapon was stolen, a vehicle matching the description of the one connected to Nieman’s slaying was stolen from a Port Allen home several houses down from Brown’s home.

Adams said later in the press conference that when Colorado officials located Brown’s stolen handgun, in the possession of an unidentified third party, the weapon was sent back to Louisiana. Adams said it was then sold at a public auction, making it difficult for Oklahoma authorities to track, but they eventually recovered it to match with the homicide.

The three suspects — Zachary Wilson, Timothy Dees and Jeremy Scott — all were arrested in February after a cold case detective re-ran the 2013 crime scene casings through the department's filing system and found they partially matched a casing that had been entered by the Denver Police Department. Wilson and Dees were arrested soon after in Mobile, Alabama, and Scott several days later in Colorado.

Follow Emma Kennedy on Twitter, @byemmakennedy.