The search for the pilot of an unresponsive twin-engine plane that drew the attention of the U.S. government and crashed in the Gulf of Mexico has been called off.

Authorities identified the sole occupant of the Cessna 421 as Dr. Peter Hertzak from New Orleans.

The plane began flying in circles for hours over the Gulf not long after takeoff April 19 from Slidell, La., en route to Sarasota, Fla. Two F-15 fighters were dispatched to monitor the aircraft.

Bill Huete, an airport mechanic told the Associated Press that Hertzak was a top-notch pilot. "He flew by the book and he didn't scrimp on maintenance," Huete said.

Below is a timeline of the events as they happened.

4 p.m. ET Approximate arrival of Coast Guard Coho Cutter water-rescue team. By then, the aircraft was completely submerged and vessels searched for debris in water about 1,500 feet deep, according to the Coast Guard.

2 p.m. ET Coast Guard helicopter crew arrives on scene. The plane is mostly intact and the nose is reported to be submerged.

12:15 p.m. ET The plane goes down approximately 120 miles west of Tampa, Fla.

9:30 a.m. ET Two F-15 fighters under the direction of North American Aerospace Defense Command (NORAD) out of 159th Fighter Wing in New Orleans, La., intercepted and monitored the circling aircraft over the Gulf of Mexico. Upon intercepting the aircraft, the F-15 pilots reported the pilot was not responding to communications. They make visual contact with the plane and report that the craft's windows were fogged over. NORAD notifies the Coast Guard 8th District watchstanders of the craft. Plane thought to be running out of fuel.

9 a.m.ET Plane circling at 28,000 feet. FAA reported to lose radio contact.

A Cessna 421 departed Slidell, La., en route to Sarasota, Fla. Only the pilot is thought to be on board.

Photo caption: A screen grab from FlightAware.com shows where the plane went wayward over the Gulf of Mexico.