HARRISBURG, Pa. - Someone appears to have deliberately tried to release bedbugs in a Walmart store in Pennsylvania, and police are searching for whoever was behind it, authorities said Monday.

Troopers have made no arrests and do not have any suspects, said Trooper Cindy Schic, a state police spokeswoman.

A manager from the Walmart store in Edinboro, in northwestern Pennsylvania, contacted police Saturday after store employees found pill bottles with bugs in them.

Some elements of the story, including whether the bugs were alive, are in dispute.

It started Thursday, when store staff found a closed pill bottle containing live bugs, authorities said. The bottle was found in a boy’s jacket for sale in the clothing department and thrown out in the trash, police said. A day later, a hygiene services contractor contacted by Walmart found bugs crawling in the men’s fitting room and identified them as bedbugs, police said.

However, a Walmart spokeswoman contended Monday that the contractor, Ecolab, told Walmart that it had found no live bugs.

On Saturday, a store worker found a second pill bottle on the floor of the men’s department. It was closed and contained several dead bugs, police said.

Troopers were testing for fingerprints on the bottle while store officials were reviewing surveillance video, police said. Walmart said it was taking the matter seriously, including co-operating with police

A Walmart spokeswoman said she did not know whether the store had had to throw away any merchandise.

Any criminal charge would be disorderly conduct stemming from public inconvenience, annoyance and alarm, a misdemeanour, Schic said.

The U.S. Centers for Disease Control and Prevention say bedbugs live off the blood of people and animals, and can hide for long periods of time, even without a meal. They are usually transported by travellers, stowing away in luggage and clothes and otherwise hiding in bedding and furniture, the agency says.