The Oklahoma Highway Patrol told Fox affiliate KOKH FOX 25 the shooting happened just before 10 a.m. in the parking lot of a Walmart in Duncan, located roughly 75 miles south of the state capital of Oklahoma City.

The Duncan Police Department said on Facebook that the woman and one of the men were found shot to death in a car, while the other man was found dead outside the car in the parking lot.

“A handgun was found on scene,” police said. “We will update as more information comes in.”

Duncan Police Chief Danny Ford told the Associated Press that authorities are looking for witnesses to the shooting. One of the people found dead on Monday is believed to have been the shooter, though additional details have not been released.

A dispatcher told the Associated Press that “everyone is at the scene.”

Aerial images from Oklahoma City television station KWTV/KOTV showed police tape covering part of the parking lot as first responders combed through the area.

Authorities marked the location of shell casings around one red vehicle, where bullet holes could be seen in the windshield of the car.

Family members at the scene told FOX25 the shooting was the result of a domestic dispute between a husband and wife.

“Law enforcement officers have secured the scene, and we do not believe there is an additional threat to the community,” Duncan City Manager Kimberly Meek said in a statement. “Our prayers are with the victims, their families and with our law enforcement community as they investigate.”

The Duncan Public Schools said on Facebook that schools were placed on lockdown due to the shooting, but have since been given the all-clear by police.

No staff members were involved in the shooting and the store was not evacuated, Walmart spokeswoman LeMia Jenkins said in an email.

“This was an isolated incident in the parking lot and was not an active shooter situation,” Jenkins said.

The incident in Oklahoma happened less than a week after a Walmart in El Paso, Texas reopened nearly three months after a gunman killed 22 people and injured dozens more at the store in August.

The 32-year-old, Tommy Lee Jenkins started an X-rated instant-message conversation with”Kylee” a teen in Wisconsin who, according to the US Attorney’s Office, was actually a Sheriff’s deputy.

Officials said also that while Jenkins pressured her to meet him for sex in Whitestown, Ind., he also asked her for asexually explicit photographs.

When she turned him down, he started on his journey to meet the 14-year-old in Neenah, Wisconsin, where she reportedly was. And repeatedly, he sent her updates on his progress of his trek.

Sadly, his very plausible trek was put to an end with a shocker – Sheriff’s deputies and an FBI agent waiting to nab him, authorities said on Friday.

Facing 10 years to life in prison if convicted, Jenkins was charged with trying to persuade, induce and also entice a minor to be a part of unlawful sexual activity using a computer.

His conversations to ‘Kylee” also included telling her he wanted them to have 500 kids together, including one within a year, according to the Oshkosh Northwestern.

“Our nation faces an epidemic of child sexual abuse, with the Internet making it too easy for predators to communicate with children across the country,” said US Attorney Matthew Krueger.