UPDATED: 9:47 am EDT September 28, 2008

FORESTVILLE, Md. -- A medical helicopter carrying victims of a traffic accident crashed in a suburban Washington park early Sunday after reporting bad weather, killing four of the five people aboard, authorities said.

Stephen H. Bunker, the helicopter pilot; Micky Lippy, the co-pilot and a flight paramedic; Tonya Mallard, an emergency responder; and Ashley Youngler, one of the traffic accident victims, died in the crash, authorities said.

Jordon Wells, who injured in the traffic accident, survived, and was rushed to a hospital by ambulance. Wells, 18, was critically injured.

It was foggy and rainy in the area about the time of the crash, said National Weather Service meteorologist Jim Decarfel.

Maryland State Police fly the medical helicopters in the state, and it was their first deadly crash since 1986 when a helicopter went down in fog in West Baltimore.

Just before midnight Saturday, the helicopter reported bad weather on the way to a Prince George's county hospital and the crew said it needed to land at Andrews Air Force Base, where it was to meet ambulances to take the accident victims the rest of the way to the hospital, authorities said.

The helicopter then disappeared from radar and officials lost radio contact. Public safety officials found the wreckage about two hours later on a trail in a wooded area of Walker Mill Regional Park.

The National Transportation Safety Board and the Federal Aviation Administration were investigating.

Bunker, 59, of Waldorf, Md., joined the Maryland State Police in 1972 and later rejoined as a civilian pilot after retiring as a corporal.

Mallard, 38, also of Waldorf, is survived by her husband and two children.

Maryland State Police Aviation Command flies 12 twin-engine helicopters out of eight bases across the state. The last fatal crash in 1986 killed two troopers who had just transported a shooting victim. The command had two other fatal helicopter crashes in the 1970s.

A recent state legislative audit faulted the police agency for failing to document maintenance needs and costs and failing to comply with federal and manufacturer repair orders. Nine of the choppers are more than 18 years old.

But state police have defended the command, and the audit noted that the operation is highly regarded throughout the nation and has an "impeccable" safety record.