A man accused of knocking down an autistic New York boy during a cross-country race has surrendered to police.

Rochester police say 57-year-old Martin MacDonald, of Pittsford, turned himself in Thursday to face a harassment charge stemming from the Oct. 14 encounter with 15-year-old Chase Coleman in an intersection.

MacDonald told investigators he got out of his car and shoved Chase during the road race because he feared the boy would try to steal his wife's purse.

Chase is unable to speak. Relatives say he wouldn't have understood anything MacDonald said to him.

The black teen's mother questioned whether race was a factor when the white man wasn't initially charged. Police renewed their investigation, and an arrest warrant was issued Wednesday.

MacDonald couldn't be reached for comment Thursday.