PORTLAND, Maine (AP) — A dock worker has pleaded guilty to making a fake distress call in December that resulted in a fruitless, many-hour search by the Coast Guard.

Nathan Libby, 31, pleaded guilty to communicating a false distress call in U.S. District Court in Portland on Thursday, The Courier-Gazette reported.

The Coast Guard said it received a distress call around 6:31 a.m. on Dec. 3, 2020, that a boat was taking on water.

“Mayday. Mayday. We lost our rudder. And we’re taking on water fast. We don’t have enough pumps to keep up with it,” an unidentified man said in a recording released by the Coast Guard soon after the call.

The Coast Guard searched for several hours in the area near Spruce Head, located about 9 miles (14.5 kilometers) south of Rockland, until it determined that there were no indications of distress or missing people in the area.

In an affidavit, the Coast Guard said a Maine Marine Patrol officer actually spoke with Libby, who was working at the Spruce Head Fisherman’s Co-op nearby, and gave the officer a list of boats that had gone out that morning.

The officer played the audio recording to another person at the co-op who said it sounded like Libby. The officer then recorded Libby’s voice and the Coast Guard consulted with a research professor at the Language Technologies Institute School of Computer Science at Carnegie Mellon University in Pittsburgh. The professor confirmed Libby’s voice matched the voice on the recording.

Surveillance footage also shows Libby was at the co-op’s office at the time of the call. The office had a radio dialed into the same channel used to make the call.

It is not clear why Libby made the distress call, but it happened just weeks after four Maine fisherman died when their boat, Emmy Rose, sank on the way from Portland, Maine, to Gloucester, Massachusetts.