MITCHELL, S.D. (AP) — The driver in the crash that killed a 14-year-old boy in Mitchell last month has pleaded not guilty to multiple charges stemming from the incident. The Daily Republic reports (http://bit.ly/1IpEZ4H ) 22-year-old Karla Martinez entered not guilty pleas Tuesday to charges including third-offense drunken driving and vehicular homicide. Martinez's sports utility vehicle rolled in the ditch off a gravel road west of Mitchell June 25.