Dallas ISD police officer shot, seriously injured, in parking lot of Northwest Dallas Sam's Club

A Dallas Independent School District police officer was shot and injured in the parking lot of a Sam's Club in Northwest Dallas late Thursday morning.

The officer suffered serious injuries and was taken to Parkland Hospital, where he was undergoing surgery. CBS News Texas's JD Miles reported that the officer is expected to survive.

In a news conference early Thursday afternoon, Dallas ISD Police Chief Albert Martinez said officer Justin Jones was flagged down to help a person on the nearby highway, I-635. Jones picked up the person to get them out of harm's way and brought them to the parking lot, off I-635 and Midway Road. 

The person then shot Jones, 39, Martinez said. He did not say what exactly led up to the shooting.

Another DISD officer responded to the scene and used a tourniquet on Jones until paramedics arrived, Martinez said.

Video from the scene showed an officer examining a Dallas ISD police vehicle with multiple evidence markers around it.

Dallas Police Chief Daniel Comeaux said a suspect is in custody and the investigation is ongoing.

Sammy Garcia, who was inside the Sam's Club with his daughter and granddaughter, told CBS News Texas's Marissa Armas that police kept shoppers inside the store for about 40 minutes. 

"They were very nervous, very scared, of course. Never been in a situation like this," Garcia said.

A Walmart spokesperson said they are working to resume operations as soon as possible.

"The safety of our associates and members is a top priority. We're working with law enforcement as they continue to investigate."

The store has since reopened.