A Texas deputy constable was killed and two others injured while working a security job early Saturday morning in Houston. The three deputies were shot while they were arresting an individual for a possible robbery, according to KHOU 11.

One of the injured deputies, who was shot in the back, remains in critical condition at a local hospital, reported KHOU 11. The third officer was shot in the foot. We believe they were ambushed, shot from behind by a suspect with a rifle,” Executive Assistant Chief of the Houston Police Department James Jones said, according to CBS News.

“My main concern is the families of the three officers involved … I hope for swift and quick justice for that individual because he ambushed my deputies,” Harris County Precinct 4 Constable Mark Herman said, reported KHOU 11.

A suspect is in custody, but police are unsure whether he was a witness or is the suspected gunman, KHOU 11 reported.