A medical helicopter crash killed a patient and injured a medical worker on Tuesday near Tulsa, Oklahoma.

According to Choctaw Nation Health Services, an investigation into the crash and the safety record of EagleMed, the company that owned the helicopter, is now underway. EagleMed is a medical transport company that operates around 20 different locations throughout the midwestern U.S.

The helicopter crashed on Tuesday night, less than 100 feet away from Choctaw Nation Healthcare Center (CNHCC) near Talihina, Oklahoma, where it had taken off from on the way to Tulsa. Though hospital emergency workers were nearby to treat the passengers, 49-year-old Michael Wilson, the patient on the flight, died. One member of the flight crew was critically injured, and was taken to a trauma center in Tulsa. The two other members of the crew were not seriously injured.

“Our staff responded extremely well to this unfortunate tragedy”, said Teresa Jackson, CNHCC CEO. “We engaged our disaster plan within moments of the accident, and the response from our staff as well as the local and state emergency personnel in the area was outstanding.”

The cause of the crash has yet to be determined, though the Federal Aviation Administration (FAA), the National Transportation Safety Board (NTSB), Choctaw Nation law enforcement officials, and an Eagle Med safety team are all currently investigating the incident.

EagleMed has expressed its thanks to well-wishers during what it calls a “difficult time.”

According to Tulsa’s KXII news station, this is the third EagleMed helicopter to have crashed in just the state of Oklahoma since 2010.