NEW : Forensic evidence leads police to investigate , sheriff says . NEW : Police are still searching for Sierra LaMar 's killer . NEW : The suspect is also linked to a 2009 unsolved assault . The suspect faces assault and battery charges .
NEW : Forensic evidence led authorities to suspect , sheriff says . NEW : Police are still searching for Sierra LaMar 's body . NEW : The suspect is also linked to a 2009 unsolved assault . The suspect faces murder and kidnapping charges .