BOSTON -- A would-be crook chose the wrong convenience store clerk to rob in Gloucester Tuesday.

The entire showdown was caught on surveillance video that Gloucester authorities said was some of the best they've ever seen.

Just as the clerk was opening the register, the robber came in, threw the lottery machine to the ground and lunged at the clerk.

But the clerk was ready for him, armed with a hammer.

As the clerk managed to get the robber into a head lock, a customer jumped in and also took a few swipes with the hammer.

The clerk's co-worker said the clerk was just acting in self defense.

"He thought, if [the thief] could do it, he could hold the machine and jump over, [then] he might be able to hurt him too. That's why he just tried to save him self," Nomi Bhatta said.

Police arrested Ricky Marshall, 27, after a dog that he brought to the scene, led police to his front door.

Marshall is being held on $10,000 bail.