A three-member medical evac team was killed in a chopper crash in Oklahoma on Saturday night, with the National Transportation Safety Board now investigating the tragic mishap.

The crew of the Air Evac Lifeteam, based in Weatherford, Oklahoma, went down shortly before 11:30 p.m. after transporting a patient to Oklahoma City, the agency said in a Facebook post on Sunday.

“Our primary focus is on supporting the families and our team members,” Air Evac Lifeteam said in the post. “[Critical Incident Street Management] teams have been sent to assist our team members during this time.

“At this time we are not sharing the names of the crew members aboard the flight,” they wrote. “AEL has turned over the scene and investigation to the NTSB.”

The Bell 206L3 chopper with the call sign N295AE lost contact with the control center around 11:23 p.m. before it crashed near Hydro, about 65 miles west of Oklahoma City, The Oklahoman reported.

The evac crew consists of a pilot, a flight nurse and a flight paramedic, the outlet said.

Air Evac Lifeteam provides helicopter and ambulance transport, with more than 150 choppers in service across 18 states, according to the group’s website.