Two men tried to rob a Whataburger, but an off-duty cop stopped by — and he was armed

An early morning Whataburger run turned into a parking lot shooting for an off-duty Dallas police officer after he arrived at the restaurant to see an in-progress robbery attempt, the Fort Worth Star-Telegram reported.

Two suspects were wounded after an 11-year veteran of the Dallas Police Department opened fire outside a Whataburger in west Fort Worth, derailing the attempted armed robbery.

Police arrested the suspects, who have been identified as 19-year-olds Ladarious Shelby and Aaron Coleman; as of Sunday, one of them was in serious but stable condition and the other had been treated for a non-life-threatening injury.

What happened?

The officer, who has not yet been identified, was off-duty and stopping by the Whataburger at about 4 a.m. Sunday morning.

Simultaneously, Fort Worth police received reports that a man wearing a mask and a black hooded jacket was waving a gun at people inside.

The exact details of the confrontation haven't been publicized yet, but the Star-Telegram reported that the officer witnessed the robbery inside and waited for the suspects to come out so he could meet them in the parking lot.

At least one of the suspects was armed. The officer fired shots at them, wounding both of them and apprehending one of them on the spot. The other suspect tried to escape, but was quickly detained by the Dallas officer and two Fort Worth officers who had arrived on the scene.

"One injured suspect was apprehended on the parking lot of the business," police spokesman Daniel Segura said in an email to the Star-Telegram. "The second one fled to a nearby business open area where he was later found and apprehended."

Police reported that a third suspect, who has not been identified, drove away from the scene of the crime.

What now?

The two suspects will face charges of aggravated robbery, according to jail records obtained by the Star-Telegram.

Dallas police will open an administrative investigation into the officer who shot the suspects.