A passenger on a motorcycle was killed in an accident in Delaware County Sunday night.

Dead is Andrea Kay Adkins, 39, of Vermilion, Ohio, according to the Delaware post of the Ohio State Highway Patrol.

Troopers say they are investigating the crash that occurred about 11 p.m. Sunday on Wilson Road, just east of Carters Corner Road in Kingston Township, Delaware County.

Brett L. Stewart, 48, of Fredericktown, Ohio, was operating a 2012 Harley Davidson Electra Glide Ultra motorcycle northeast-bound on Wilson Road. The motorcycle went off the right side of the road, and Stewart lost control. The motorcycle overturned as it came back onto the road before coming to rest, troopers said.

Stewart was transported by helicopter to OSU Medical Center in Columbus with serious injuries.

Adkins was pronounced dead at the scene, troopers said.

Alcohol is believed to have been a factor in the crash, troopers said.

Adkins was wearing a motorcycle helmet, they said. Troopers said they do not know if Stewart was wearing a helmet.

The crash remains under investigation.