Armed with fake Amazon boxes, doorbell cameras, and GPS for tracking, the Jersey City Police Department believes it has found a way to catch thieves hoping to swipe products purchased on the e-commerce site. According to the Associated Press, the Jersey City police place the fake Amazon boxes on porches in front of a doorbell camera. They then wait for a would-be thief to walk by and swipe the box. In a sting on Tuesday, it took them just three minutes before a thief tried to steal a box, says the AP.

Amazon partnered with the police by providing equipment and boxes for the sting operation.

Porch theft has become an increasingly concerning problem as people turn to e-commerce sites for the bulk of their shopping. In response, Amazon has launched programs, including Amazon Key, that allow customers to securely let delivery people leave their purchases in their car trunks or inside their home.

Still, the vast majority of people that buy products on Amazon (AMZN) or anywhere else don’t use those services. So, they’re left to hope that the products they purchase will still be on their porch when they get home.

Looking ahead, Jersey City said that the sting operation’s success means it’ll expand it to other parts of the city. In a statement to the AP, Amazon said that it remains “committed to assisting” Jersey City police in their operation.