BELLEVUE, Neb. (NewsNation Now) — Authorities arrested a 23-year-old man in an attack at a Nebraska fast food restaurant in which two employees were shot and killed, two were wounded and officers responding to a report of a possible bomb inside a moving truck in the parking lot arrived to find the vehicle on fire.

Roberto Carlos Silva Jr., of Omaha, was booked into Sarpy County jail early Sunday on suspicion of first-degree murder and first-degree arson in Saturday night’s attack at a Sonic Drive-in restaurant in Bellevue, the Omaha World-Herald reported. Silva was being held without bond Sunday before making his initial court appearance.

In a news release early Sunday, Lt. Andy Jashinske said Bellevue police received a call at 9:23 p.m. Saturday about a possible bomb in a U-Haul truck parked outside of the restaurant in the Omaha suburb. A minute later, the call was updated to a possible shooting, he said.

Officers who arrived found the moving truck burning and four restaurant employees who had been shot. Two were sent to the University of Nebraska Medical Center for treatment, and the other two were declared dead at the scene, Jashinske said.

Police identified those killed as Nathan Pastrana, 22, and Ryan Helbert, 28. The two employees who were taken to the hospital are Zoey Reece Atalig Lujan, 18, and Kenneth Gerner, 25. A fifth Sonic employee suffered a minor injury but declined treatment at a hospital.

The Omaha Police Department’s bomb squad was at the scene early Sunday to check on a “device,” as a precaution to make sure the area was safe, Jashinske said. They determined there was no bomb.

The attack came days after Silva was arrested outside of the restaurant after allegedly using someone else’s Sonic app account to buy a total of $57 worth of hamburgers and corn dogs in four separate purchases at that location, the World-Herald reported. Silva was released from jail on Thursday after posting 10% of his $1,500 bail. At the time of that arrest, police seized three firearms from Silva, and police still held those weapons, Jashinske said Sunday.

After the shooting, police seized four firearms, though Silva was unarmed and didn’t resist when he was arrested outside the restaurant, Jashinske said.

Jashinske said the investigation was in its “infancy,” and he couldn’t explain what led to the shooting.

Sonic Drive-in, which is based in Oklahoma City, issued a statement Sunday saying the company was “stunned and saddened by what occurred at the Bellevue, Nebraska, Sonic Saturday night. Our heartfelt condolences go out to the franchise owner and the families and friends impacted by this horrific tragedy.”