LEAVENWORTH, Kan. -- The search was on Thursday for a gunman who had Leavenworth's delivery drivers on edge.

Leavenworth police believed the gunman had struck twice in a week, first hitting a Sonic drive-in restaurant and the next night holding up a pizza delivery man, and they warned especially food delivery people to be very careful.

Papa John's changed some of its delivery policies in Leavenworth after a man with a shotgun held up one of its employees in front of a vacant house at North Fourth and Cheyenne streets Tuesday night.

Someone had ordered a pizza but was after much more than food.

"I do believe it was very likely a set-up, a ruse, to get the delivery driver to come to a house that wasn't occupied," said Leavenworth Police Chief Pat Kitchens.

One pizza delivery driver -- not the most recent victim -- said he had been robbed before.

"If I pull up to a house if there are no lights on and it just doesn't look like anyone's at home, grass is high, I just keep on going, especially if someone is standing outside watching," the driver said.

Papa John's plans to work harder to verify callers and their addresses, and their delivery people have been told not to stop if there is anything suspicious.

Leavenworth police have offered to come along on a delivery if an employee is concerned.

It's a policy the delivery driver said everyone should follow.

"I'm always concerned about it," he said. "I've been robbed at another store and it wasn't fun. It wasn't fun getting that gun stuck in your face."

Leavenworth police said a neighbor found a shotgun in his yard that they were checking to see if it was the weapon the robber used in the pizza delivery hold-up.

They said they were linking the robbery of the delivery man to the Sonic robbery because of very similar suspect descriptions.