HONOLULU -- Military divers searched Honolulu Harbor Tuesday after a Coast Guard sentry reported a scuba diver in the water Monday night.

Recreational divers aren't allowed in the harbor. The sighting raised more red flags because the diver was reported near the Coast Guard's 47-foot patrol boat moored at the Sand Island base.

The Coast Guard organized the search, which eventually included Army and Navy divers, state law enforcement and joint terrorism task force agencies, including the FBI.

"I thought it was big joke. You know what I mean? But, he gave me the card," diver John Neal said.

Neal dives along Sand Island State Park. An FBI agent asked for his help.

"They told me that if I jump in the water, if I find anything, diving scuba tanks or whatever, call him up. He gave me the card," Neal said.

The Navy divers were experts in bomb disposal and joined Army divers searching around and under piers near, where the suspected diver was seen.

Even after nothing was found, the Coast Guard kept its presence up in the harbor channel and offshore, under the take-off routes from Honolulu International Airport.

The Coast Guard commander would not be interviewed about what happened even though nothing was found. He said they are confident that there is no threat to the port of Honolulu.