JALAPA, S.C. --  A medical helicopter crashed Tuesday in a wooded area about 50 miles northwest of Columbia, S.C., killing four people.

The victims include a woman who was being flown to the hospital after getting hurt in a hit-and-run at a highway rest stop. Also killed were the pilot, a flight nurse and a paramedic.

A witness who watched the helicopter take off said he heard a "boom" after the chopper got above the trees. There was no word on the cause of the crash.

Weather conditions in the area were said to be foggy at the time.

Much of the upstate had foggy conditions Tuesday morning, but it's unknown if the fog played any part in the crash.

Spartanburg Regional Medical Center spokeswoman Betsy McMillan said the four people onboard who died in the crash include:

Bob Giard, 41, pilot
David S. Bacon Jr., 31, paramedic
Glenda Tessnear, 38, flight nurse
 

Giard had flown Regional One since the program began in 2003. Bacon had worked with the program since May 2003, while Tessnear had been a part-time flight nurse for the past six months.

Regional One began service from SRMC in March 2003, using a Bell 407 helicopter. It is one of three medical helicopter services operating in the upstate. Regional One and Med Trans One, which operates out of Greenville County, are owned by N.D-based Med Trans Corp.

Regional One is one of 11 helicopter services operated by Med Trans.

Bacon had just received his national flight paramedic certification.

"It's just kind of odd, because in my inbox this morning, he made a copy of the certificate. He just received that in the mail yesterday," Silk said.

A memorial service is scheduled for 10 a.m. Thursday at the hospital helipad.

Meanwhile, nine hours after the crash, investigators continued to pour over debris from the crashed helicopter, looking for clues as to why it crashed.

What remained of the helicopter was scattered over an area smaller than a football field. Some small debris remained stuck in trees where the chopper went down. Motor parts, wires, fiberglass from the body of the helicopter and an oxygen tank could be seen.

A small piece of green metal with an "H" on it peeked out of the white foam firefighters sprayed on the wreckage to make sure it didn't re-ignite.

Officials from the National Transportation Safety Board are on the way to the scene, and Federal Aviation Administration investigators are en route to investigate.

Images Of The Regional One Crash Scene And Investigation