The body of a woman discovered in a wooded area in Chelmsford Monday afternoon is that of a Lowell woman reported missing last month, police say.A massive search was launched Oct. 25 when Elga Crespo, 67, was reported missing.Chelmsford police said Monday that a woman's body was found off Technology Drive between a restaurant and parking lots of the Environmental Protection Agency.An autopsy confirmed that body was that of Crespo.There was no obvious sign of foul play, and the cause of death is under investigation by police and the Middlesex District Attorney's Office.Police described Crespo as "mentally challenged" and said she had the mental capacity of an 8-year-old. She was also reported to be diabetic and was on several medications.