By Tim Ghianni

NASHVILLE Tenn. (Reuters) - A Good Samaritan who stopped to help at the scene of a car crash on Friday died after stepping over a bridge railing and plummeting into a river far below, Nashville police said.

Mark A. Ferguson, 27, of Omaha, Nebraska, probably believed there was land on the other side when he stepped over the railing and fell into the Stones River, the Nashville police said in a news release. Ferguson was able to swim to the bank of the river, but he was pronounced dead after being taken by ambulance to Vanderbilt University Medical Center.

Ferguson and his three brothers were driving on Interstate 40 through Nashville when they came upon a car that had crashed into the retaining wall and was partially blocking the interstate early on Friday morning, police said.

They stopped to help, but the driver was nowhere to be found. A witness who had stopped told the Fergusons the driver had left the scene, possibly in the direction of nearby woods. Ferguson went in that direction, but then fell into the river.

Police found the driver of the crashed car nearby. Nathan Earl Albright, 36, of Nashville showed signs of impairment and admitted to drinking alcohol prior to the crash, according to police.

He was arrested on charges of driving under the influence and refusing to take the breath/alcohol test. He is jailed on $5,000 bond, police said.

(Reporting by Tim Ghianni; Editing by Mary Wisniewski and Sandra Maler)