Three crew members aboard a private medical helicopter died in a crash Monday night while flying over northern Kentucky en route to pick up and Thurston Cartetransport a patient, officials said.

The crash occurred before 6 p.m. EST as the helicopter, run by Air Evac Lifeteam, was traveling over Owenton, located about halfway between Louisville and the Ohio border near Cincinnati. The company, which operates out of 150 air medical bases in 18 states, shared the news late Monday night in a Facebook post.

"This was a terribly tragic accident, and our deepest sympathies go out to the employees’ families and friends," Air Evac Lifeteam said in the statement. "Our primary focus now is on supporting the families who were impacted as well as our team members."

Deadly plane crash:'Multiple' deaths reported after single-engine plane crashes in North Carolina

Helicopter crash occurred between Louisville, Cincinnati

The crew, who were based out of an airbase in the neighboring Grant County, had been dispatched for a medical transport when the crash occurred, according to the Kentucky State Police.

Troopers were called at 5:34 p.m. to the scene in Owenton, which was near east Kentucky Highway 22, according to a news release provided to USA TODAY. It was not immediately clear where the medical helicopter had been headed before crashing.

All three crew members aboard the vehicle, identified by state police as Gale Alleman, Bethany Aicken, and James Welsh, were pronounced dead at the scene. The agency did not provide ages.

Federal investigation into crash underway

The National Transportation and Safety Board will investigate what caused the helicopter to crash, according to the Federal Aviation Administration. The FAA identified the craft as a two-bladed, twin-engine Bell 206 helicopter.

An NTSB investigator is expected to arrive Tuesday afternoon at the scene of the crash to begin documenting the scene and examining the downed aircraft, according to a statement provided to USA TODAY. Investigators will also analyze radar data, weather information, maintenance records and the pilot’s medical records.

A preliminary report is expected within 30 days of the crash before a final report is completed within one-to-two years, the NTSB said in its statement. Witnesses or those with surveillance video or other information can contact the NTSB at [email protected]. 

Air Evac Lifeteam said in its statement that the company is cooperating with the investigation.

"Critical incident stress management teams have been sent to assist our team members during this difficult time," the company added. "We kindly request respect for the privacy of our team members and their families in this difficult time."

This story has been updated to add new information.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]