identified a potential lead. >> they were able to track a scent trail to a residential area in concord that was very close to the canal trail. >> a background check revealed a man living in this neighborhood had a criminal history. he also looked similar to the composite drawings. his name was mark fisher. >> he was known to be violent, violent to his relatives, violent to police officers and to other public officials. >> witnesses in the park were shown a photo lineup which included fisher's picture. >> at least three of the witnesses were positive that the photo of mr. fisher was the subject they had seen on the trail. >> but when investigators went to fisher's house, they got some shocking news. >> the police were met by a relative who told them, you haven't heard? my brother, mr. fisher, just killed himself, jumped off the golden gate bridge, committed suicide.