FRANKSVILLE, Wis.—A man filling up his car at a Wisconsin gas station was shot and killed by another man on Tuesday, with the suspect fleeing the scene and dying soon after in a shootout with an undercover sheriff’s investigator. Racine County Sheriff Christopher Schmaling said the initial shooting happened about 7:30 a.m. at the Pilot Travel Center in the village of Caledonia. Schmaling said a 32-year-old man approached and “viciously executed” a 22-year-old man putting gas in his car. Schmaling said the gunman then shot at another person driving through the Pilot parking lot — that person was unhurt — and then drove away. The sheriff said the man then approached a person who was filling up his car at a Mobil station about 2 miles away. That man happened to be an undercover sheriff’s investigator with 21 years of experience, Schmaling said. He said the two men exchanged gunfire, …