Dallas police say they believe someone in the department stole more than 15,000 rounds of ammunition from the department's shooting range.
A routine inventory check Wednesday morning revealed 38 cases of missing ammunition.
Investigators said they suspect the theft was an inside job because only a handful of officers have access to the storage bunkers at the southwest Dallas training center.
"To load 38 cases of ammunition from a building to a vehicle -- somebody is going to see it," said gun salesman Chuck Pay, a salesman at Ray's Sporting Goods.
Dallas police said they are reviewing surveillance video from the range.
"Who's to say he didn't take one case here, two cases there and then three cases," Pay said.
While stealing that much ammunition may take time, the thief can get rid of it in no time, Pay said.
"It's in short supply," he said. "You can call around to some shops around here, and they don't have any ammunition to sell you."
With supply down, ammunition prices are up. Pay said ammo is selling for twice what it did a year ago.
Dallas police valued the ammunition at $4,700. Police said their internal investigation could take several months.