JALAPA, S.C. -- A woman who was injured in a minor hit-and-run accident ended up getting killed on the way to the hospital.

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 minor 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 fair 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.