By Andy Rose, CNN

(CNN) — Three people were fatally shot Sunday night at a convenience store in Garland, Texas, police said. A fourth victim was hospitalized in critical condition.

Lt. Pedro Barineau with the Garland Police Department says surveillance video from the Texaco station showed a man leave a pickup truck and immediately begin firing after entering the store. He then returned to the truck, which was driven by another person.

Neither the suspect nor the getaway driver has been identified.

"This does not appear to be a robbery," Barrineau told CNN. He said investigators are not yet sure whether the shooter knew the victims.

Garland is part of the north Texas "Metroplex," just northeast of Dallas.

Garland police investigate a fatal shooing scene at a convenience store on December 26, 2021.

™ & © 2021 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.