MONROE — The arrest last week of a Benton volunteer firefighter on a tentative charge of impersonating a peace officer highlights how seriously the Green County Sheriff's Office takes misuse of emergency lights and sirens.

Austin T. Erdenberger, 21, was cooperative with deputies when arrested June 17 and "readily admitted" he was a firefighter with the fire department in Stitzer, an unincorporated village just south of Fennimore in Grant County, said Sheriff Mark Rohloff.

But deputies also found sufficient evidence that Erdenberger had impersonated a peace officer by reportedly using flashing emergency lights on his personal vehicle to "pull over" two women. The charge is a Class H felony in Wisconsin.

Charges or citations against Erdenberger had yet to be filed in Green County Circuit Court as of Monday, pending a decision from the District Attorney's office. State court records show no criminal history for Erdenberger. The records do show he's received five speeding tickets and a few other minor traffic violations since 2014.

The investigation began with a traffic complaint reported at about 6:45 p.m. June 17 south of Brodhead on Wisconsin 81 east of County GG, Spring Grove. The complaint came from two women, a 21-year-old driver and her 41-year-old passenger, who are not local and were passing through.

"Apparently he was first observed by our victims in Beloit," Rohloff said. "They encountered him at a stoplight in Beloit. ... When they first saw him, they saw the car had a lot of antennas and emergency lights."

The women later told deputies his car was driving erratically "all over the road" so they passed him. In response, he activated a siren and flashing lights on his 2014 Chevy Cruze. They pulled over to the side of the road, believing he was a police officer. But his vehicle "sped off" past them, "and that's when they contacted us," Rohloff said.

Deputies located and stopped Erdenberger near Monroe. After his arrest, he posted bond and was released pending court.

Erdenberger claimed he "got flipped off and that incensed him to some degree," but this wouldn't excuse misuse of official emergency equipment, Rohloff said.

Deputies found a siren box, scanner, antennas and a light bar with a programmable light system in Erdenberger's car.

"All those things gave rise to suspicions," Rohloff said.

Fire department-issued equipment like this is only authorized for use in that specific fire district and is a privilege that shouldn't be abused, he added.

"The thing is, we have a definite problem here," Rohloff said. "When we have female victims in a car being pulled over by a man who's purporting himself to be a police officer, that really makes me concerned about victimization."

However, Rohloff said, no one was endangered in the incident and Erdenberger didn't approach the women's car on foot. Based on Erdenberger's admissions alone, "the more appropriate charge might be unauthorized use of flashing lights."

Erdenberger's car was initially impounded, but the District Attorney's Office decided against issuing a search warrant for it, "believing the observations and statements were sufficient," Rohloff said.

A traffic citation, and not a felony charge, could be the outcome of the investigation.

"Still, I don't believe the criminal charge was premature," Rohloff wrote in a follow-up email. "We took the complaint seriously as the victims felt threatened."