The U.S. Coast Guard has suspended its search for six people aboard a medical transport aircraft that crashed off the coast of Nantucket, Massachusetts.

The Canadian-registered Gulfstream G100 air ambulance was traveling from Bermuda to Boston when authorities lost contact with the aircraft early Saturday. Search teams later found a debris field in the Atlantic near Nantucket.

The six people aboard included four Canadians and two people from Bermuda. The aircraft was operated by Canadian air medical provider Latitude Air Ambulance, which said its four crew members, a patient and the patient's family escort are presumed to have died.

The Coast Guard said crews searched more than 4,400 miles over 66 hours using aircraft and vessels. The debris was found in waters about 80 to 90 feet deep, while authorities continue moving toward recovery and investigation efforts.

The Federal Aviation Administration had alerted the Coast Guard after losing contact with the aircraft. Investigators will examine the circumstances surrounding the crash, including reports that the pilot experienced electrical problems before the aircraft disappeared.