The US Coast Guard on October 4 suspended its search for six people aboard a medical transport aircraft that crashed into the Atlantic Ocean off the coast of Nantucket.

The Gulfstream G100, operated by Latitude Air Ambulance, was travelling from Bermuda to Boston when the Federal Aviation Administration lost contact with it at about 2 am local time on October 3. Search crews later found a debris field linked to the jet.

Searchers covered about 4,445 miles over roughly 66 hours. The Coast Guard said the search was suspended after crews found no sign of survivors.

Rear Admiral Matthew Lake, commander of the Coast Guard’s Northeast District, said suspending a search is not an easy decision. He expressed condolences to the families and thanked partner agencies.

The six people aboard included four Canadian nationals and two nationals of Bermuda. Next of kin have been notified. The cause of the incident remains under investigation.