PHOENIX - Silent Witness and Phoenix Police are offering up to a $1,000 reward for information that leads to the arrest of the man who robbed a Circle K and customer at gunpoint.

The robbery happened at the convenience store at 35th Avenue and Monte Vista on Saturday, July 28, 2017.

"When this guy comes in to commit his robbery, he's almost frantic," said Sgt. Jamie Rothschild, who's with Silent Witness.

Surveillance video shows the man walked into the store, went up to the counter and pulled out a handgun. He was shaking a black bag incessantly while demanding cash and other items from the clerk.

Then the robber walked behind the counter to grab the cash himself. In the process, he dropped the cash drawer and possibly cigarettes on the floor.

"Now he's trying to pick up those items, while holding a gun then he goes to leave and he puts a customer at gunpoint," Sgt. Rothschild said.

That customer walked up to the counter in the middle of the robbery and ended up getting a gun pointed at his head. The robber appeared to demand cash from the customer. The man tried to give it to him, but the robber had his hands full with everything else. He left and took off in a light colored four door car.

If you recognize the robber, you're asked to call Silent Witness at 480-WITNESS. You can remain anonymous and receive a reward of up to $1,000.