A helicopter operated by a rescue service has crashed in central Slovakia, killing all four people on board.

The rescue service — Air-Transport Europe — says the crash occurred late Wednesday near the village of Strelniky shortly after the rescuers took on board a man with a broken leg and the Bell 429 helicopter took off, heading to a hospital in the regional capital, Banska Bystrica.

Service spokeswoman Zuzana Hopjakova says it took several hours before the site of the crash was located early Thursday in a local forest.

The victims were identified as pilot Jan Rusin, 50, doctor Patricia Krajnakova, 46, rescuer Frantisek Bartos, 32, and the 38-year old patient.

Authorities are investigating the cause of the crash.