of TWA 800, the FBI initiated a parallel criminal investigation alongside the NTSB's accident investigation. Search and recovery operations Search and recovery operations were conducted by federal, state, and local agencies, as well as government contractors. An HH-60 Pave Hawk helicopter of the New York Air National Guard saw the explosion from about 8 miles away; it arrived at the scene of the explosion while debris was still in the process of falling into the water, forcing the crew to pull away. They reported their sighting to the tower at Suffolk County Airport. Remotely operated vehicles (ROVs), side-scan sonar, and laser line-scanning equipment were used to search for and investigate underwater debris fields. Victims and wreckage were recovered by scuba divers and ROVs; later scallop trawlers were used to recover wreckage embedded in the sea floor. In one of the largest diver-assisted salvage operations ever conducted, often working in very difficult and dangerous conditions, over 95% of the airplane wreckage was eventually recovered. The search and recovery effort identified three main areas of wreckage underwater; the yellow zone, red zone, and green zone contained wreckage from front, center, and rear sections of the airplane, respectively. The green zone with the aft portion of the aircraft was located the furthest along the flight path. Pieces of wreckage were transported by boat to shore and then by truck to leased hangar space at the former Grumman Aircraft facility in Calverton, New York, for storage, examination, and reconstruction. This facility became the command center and headquarters for the investigation. NTSB and FBI personnel were present to observe all transfers to preserve the evidentiary value of the wreckage. The cockpit voice recorder and flight data recorder were recovered by U.S. Navy divers one week after the accident; they were immediately shipped to the NTSB laboratory in Washington, DC, for readout. The victims' remains were transported to the Suffolk County Medical Examiner's Office in Hauppauge, New York. Tensions in the investigation Relatives of TWA 800 passengers and crew, as well as the media, gathered at the Ramada Plaza JFK Hotel. Many waited until the remains of their family members had been recovered, identified, and released. This hotel became known as the "Heartbreak Hotel" for its role in handling families of victims of several airliner crashes. Grief turned to anger at TWA's delay in confirming the passenger list, conflicting information from agencies and officials, and mistrust