Officials closed the beach, but Condlin said investigators later determined Lopenzo was lying.
When asked by detectives whose boat he was working on, Lopenzo gave the name of a nonexistent boat and owner, Condlin said.
There was no listing for Lopenzo in the town's directory. Condlin said he didn't know whether Lopenzo had an attorney.
A second beach was closed Thursday on the island -- where the movie "Jaws" was filmed -- after lifeguards at South Beach said they might have seen a great white shark.
The beaches were reopened Friday.
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