Gunfire at two gas stations in the Village of Caledonia left two people dead Tuesday, including a man authorities described as instigating the shootings, authorities said.

A third man, described as an undercover Racine County Sheriff investigator, suffered gunshot wounds and underwent emergency medical procedures, Racine County Sheriff Christopher Schmaling told members of the media at a press briefing streamed on Facebook about 1 p.m. Tuesday.

Authorities did not elaborate on motives for the shooting, the types of firearms used, or other details, and did not take questions at the briefing.

The incident began about 7:30 a.m. at the Pilot Travel Center at 13712 Northwestern Ave., in the Village of Caledonia when a 32-year-old man from Hartland approached a 22-year-old man from Elkhorn, and shot and killed the younger man, Schmaling said.

The first victim “was simply putting gas in his car, and was viciously executed,” Schmaling said. “I personally watched this video, ladies and gentlemen, of this horrific event and I found it to be extremely disturbing and heart-wrenching to view.”

Following the fatal shooting, the Hartland man opened fire on another customer entering the Pilot station’s parking lot, but did not injure his second prospective victim. The shooter then drove to the Mobil Station located at 10616 Northwestern Ave. in Caledonia, according to Schmaling.

The armed man next exited his vehicle and opened fire on a man filling his tank at the Mobil station, the undercover investigator wounded in the shooting, Schmaling said. The investigator was just starting his shift for the day, Schmaling said.

“The investigator and the suspect both exchanged gunfire,” he said. “The suspect was struck multiple times and died as a result of his injuries.”

Emergency medical personnel transported the sheriff’s investigator to Ascension Hospital in Racine, where was undergoing treatment for at least one injury sustained in the shooting. Schmaling described the wounded investigator as “conscious and alert.”

“There is no doubt in my mind the quick and heroic actions of our investigator saved lives today,” he said.

Wisconsin state law requires officer-involved shootings to be reviewed by at least two investigators, one identified as the lead investigator. Neither investigator can work for the law enforcement agency of the officer involved in the shooting.

Schmaling told the press that the Wisconsin Justice Department’s Division of Criminal Investigation would investigate the shootings as part of this requirement.

Neither the name of the shooter or either victim was immediately released Tuesday afternoon.