A Lufkin man who allegedly sexually assaulted a 13-year-old girl in August has been formally indicted by an Angelina County grand jury.An arrest report stated that Shawn Anthony Reagan, 23, drove the girl to his home on Fifth Street in Lufkin where he sexually assaulted her in a bedroom on Aug. 29. The girl has given statements about the incident and had a sexual assault nurse examination, the report stated.