An alligator reportedly spotted in a western Pennsylvania river may never be found — or even confirmed — but police continued to search for it Friday, the local police chief said.

Nobody has seen the reptile since two people reportedly spotted it in the Monongahela River in Belle Vernon on Tuesday, Southwest Regional Police Chief John Hartman said.

"We've continued to investigate it," Hartman said.

The initial report made by two people near a boat launch indicated the alligator was about 7 feet long.

It's possible the animal hitched a ride on a barge from a warmer spot down South, or was an exotic pet that was released by its owner or escaped into the river, Hartman said.

Police have consulted with the U.S. Coast Guard and Pittsburgh Zoo officials and determined that the alligator — if that's what it was — could survive even though the river remains relatively cold, Hartman said.

Police received several calls about the alligator on Thursday, but they weren't new sightings, the chief said. Rather, people who also thought they had seen an alligator in the river — some several weeks ago — called police to report it after Pittsburgh-area media outlets began reporting Tuesday's sighting.

"There have been no additional sightings or reports since the first two people spotted it," Hartman said.

The Coast Guard used crews to search the river's banks on Wednesday and found nothing.

Although experts have told police the alligator couldn't live in the area year-round, the cold-blooded animal would be able to survive for an extended period as long as the river wasn't frozen over. That would keep it from breathing properly in the water, Hartman said.