THE BRONX - A 13-year-old autistic boy missing since Tuesday has been found.Police say Ross Harrison was found early this morning on the J train in Brooklyn. There's no word yet on how he got there.Harrison's mom told News 12 The Bronx that her son ran out of their apartment building earlier this week after he complained about being bullied on his school bus.Police say the teen has been reunited with his parents and is unharmed.