The search is on for three men who robbed a Dallas convenience store at gunpoint early Monday.
The robbery happened a few minutes after midnight at a 7-Eleven just off of the Inwood Road exit of Interstate 35E, according to Dallas police.
Each man had a handgun with him, police said, and forced the two clerks to the floor of the store before they took money from the cash register and ran away.
Dallas police took to the skies with their helicopter, Air 1, to search for the men but found nothing, police said.
Investigators who responded to the robbery call spent more than an hour speaking with the clerks and also reviewed security tapes in the hope of being able to identify the robbers.