HUGO, Okla. (CBSDFW.COM/AP) — A mother says two of her kids suffered head wounds and a third was shot in the face as Oklahoma police fired at a man in a pickup truck who was suspected of robbing a restaurant.

“My 4-year-old daughter was shot in the head, and she has a bullet in her brain, and my 5-year-old has a skull fracture,” Olivia Hill told Sherman, Texas news station KXII-TV . “My 1-year-old baby has gunshot wounds on her face.”

Investigators and a hospital didn’t release the children’s conditions. Hill said her 2-year-old child who was also in the truck was not hurt.

Hill and the four children were in the pickup with William Devaughn Smith, 21, when officers approached him and gunfire broke out Friday in Hugo, which is near the Texas state line, Oklahoma State Bureau of Investigation spokeswoman Brooke Arbeitman said.

Police say Smith tried to get away from them and hit an officer as he was backing up his pickup truck. A second officer says he was almost hit and fired shots in fear for his safety.

Officials have not said if the officers involved knew there were children inside the vehicle.

The exact cause of the shooting is still under investigation. Smith’s relationship to Hill and the children isn’t clear.

Smith was also injured in the shooting. He was treated at a hospital and then taken into custody where he faces an aggravated robbery charge.

“What happened between the contact with him and when police fired, we’re still trying to put that together,” Arbeitman said. “The OSBI is still investigating whether he fired at police and whether he was armed.”

She said “it’s going to be a few days before we know anything,” including how many officers were involved in the shooting.

Smith is suspected in an April 11 armed robbery at a Pizza Hut in Hugo, about 150 miles southeast of Oklahoma City.

A post on the Hugo police Facebook page says a man entered the back entrance of the restaurant, pressed an object to an employee’s back and demanded money. Police said the worker handed over money and the robber left.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)