DIEHLSTADT, Mo. -- A woman was killed Friday evening in what appeared to be a horse riding accident.

The Scott County Sheriff's Department was contacted by a passer-by who reportedly spotted a woman who had apparently been thrown from a horse in the Diehlstadt area, according to Capt. Gregg Ourth.

Emergency medical service personnel arrived on the scene to find the woman, approximately age 55, with no pulse.

"Apparently she had been there for a little while," Ourth said. "She was pronounced dead by the coroner."

Scott County Coroner Scott Amick was not available for comment.