Authorities searched waters off the coast of Miami Thursday after the pilot of a small plane reported that his passenger fell out of the aircraft as it flew about 1,800 feet over the ocean.

The pilot of the Piper PA 46 told air traffic control that the lone passenger opened the plane's rear door, according to an audio recording of the call.

"Mayday! Mayday! Mayday!" he radioed. "I have a door ajar and I’m heading to [Kendall-Tamiami Executive Airport]... I have a door ajar and a passenger that fell down. I am six miles from Tamiami."

"You said you've got a passenger that fell out of your plane?" asked the air traffic controller.

"That's correct, sir," the pilot answered. "He opened the back door and he just fell out the plane."

FAA officials said the call came in about 1:30 p.m. as the pilot flew approximately a mile offshore over Biscayne Bay east of Key Biscayne. He landed safely at Tamiami after making the mayday call.

Miami-Dade Police confirmed a death investigation is underway, describing the passenger as having "jumped off or fell." Homicide detectives interviewed the pilot at the airport, and news footage showed the small plane on the ground, marked off with orange cones and surrounded by police cruisers.

“At this time the pilot is very cooperative with the investigation, he’s been talking to them all afternoon,” MDPD spokesman Lt. John Jenkins, Jr. told CBS4.

Boats and helicopters from MDPD, Miami-Dade Fire Rescue, and the U.S. Coast Guard searched the area where the man reportedly fell. Efforts were called off after dark due to inclement weather and poor visibility, police said, and will continue at daybreak Friday as a recovery mission.

“It’s safe to say someone falling out of an airplane without a parachute is going to be deceased,” Jenkins told the Miami Herald.

This is a developing news story and will be updated as more information becomes available.