Police seeking the public's help in search of 9-yr-old missing autistic boy in Va.

HANOVER, Va. (CBS/AP) - Authorities are encouraging  the public's help in the search for a 9-year-old autistic Virginia boy who disappeared on Sunday while on a walk with his family. Citizen volunteers joined the Hanover County Sheriff's Office on Tuesday in the search for Robert "Robbie" Wood Jr.

About 900 volunteers were being processed Tuesday , to help with the search, according to local news source Fredericksburg.com.

Police say the boy wandered away while with his father, brother and a woman at North Anna Battlefield Park on Sunday.

The 80-acre park is not fenced in, so officials are concerned Wood could have wandered off the property.

Wood does not speak. He has blond hair and blue eyes. He was last seen wearing a red, long-sleeved T-shirt, blue athletic pants and blue shoes.