SHERIDAN, WIS. – The discovery of four bodies inside an SUV abandoned in a cornfield has left this scenic farming region on edge, and friends and family members of the victims struggling to come to grips with the crime.

At the Bridge Stop gas station a few miles from where a local farmer found the black vehicle with Minnesota plates parked in tall corn, customers passed through Tuesday wondering why the victims — all from the St. Paul area — were left near their western Wisconsin town.

One woman at the station who declined to give her name out of fear for her safety said investigators were at the gas station Monday to review surveillance footage, and discovered that the vehicle found in the field had stopped at the gas station about noon Sunday, about two hours before it was discovered hidden 50 feet into a cornfield near the Sheridan Town Hall.

Talk of the bodies has swept through the villages that dot the rolling farmland of the region, where brown fields of drought-stricken corn and withered soybeans stand against the rock outcroppings and steep hills shaped thousands of years ago by retreating glaciers.

The Dunn County Sheriff's Office's disclosed details of the discovery Monday night in a Facebook posting that also said a second dark-colored SUV may have been traveling with the abandoned vehicle.

No arrests had been announced as of Tuesday night. Zach Pettus, of St. Paul, said Tuesday that the Sheriff's Office informed his family that the victims included his brother, Matthew Pettus, 26, and half-sister Jasmine C. Sturm, 30, both of St. Paul. Authorities told him the others killed were Sturm's boyfriend, 35-year-old Loyace Foreman III, and 30-year-old Nitosha Flug-Presley of Stillwater, a close friend of Sturm's.

"We knew something was wrong when [Sturm] didn't respond to our messages," Pettus said, adding that she and Foreman left the five children they were raising behind at their St. Paul home. "We have an idea who did it, but I don't know if I should say something now."

Pettus said nothing he knows about any of the four victims would make him suspect anything like this was possible.

"This is a freak thing that never should have happened," he said.

Sheriff Kevin Bygd said during a late-afternoon news conference in the county seat of Menomonie that investigators can't pinpoint exactly when the killings occurred but believe the four were shot within 24 hours of the SUV being found.

Bygd also said he has "a high degree of certainty" that the suspect or suspects in the killings are no longer in the area.

"We don't believe they were locals," he said. "We can't find any connection to this area, other than perhaps randomly driving out of the Twin Cities."

It doesn't appear that organized crime or drugs were involved in the case, he said. Bygd said he has no idea what the motive was behind the shooting, but "everybody is a suspect at this point. We're looking at every possibility. Hopefully, arrests will be made soon."

At the time of his death, Matthew Pettus was working at Shamrocks bar and restaurant in St. Paul, and Sturm was an office assistant for the Fields Law Firm in Minnetonka, Zach Pettus said.

Shamrocks manager Katie Schille said that Sturm also held a second job at the W. 7th Street dining spot and Matthew Pettus was a new hire.

"We're having a dinner tonight with all the employees," Schille said.

Elizabeth Brown said she and Matthew Pettus had been a couple until they broke up about six months ago but remained in contact in part because he was close with her 3-year-old daughter.

"He never mentioned anything that made you think this could happen," said Brown, who last heard from him Friday night, when he sent her photos on social media.

"Unfortunately, all four paid the price, and we don't know for what," said Brown, who also counted Sturm among her closest friends. "To drop them off in a cornfield, what kind of person are you?"

The fact that the bodies were left in a cornfield in September was a clue that the killers weren't local, said the woman at the Wheeler gas station.

"Spring and this time of year, farmers are out in their fields, checking their crops," she said. "If you're trying to hide some bodies you wouldn't put them in a field."

matt.mckinney@startribune.com 612-673-7329

paul.walsh@startribune.com 612-673-4482