What would you do if someone brutally murdered your only child, served only months in jail because of a technicality, and continually taunted, even threatened, you from behind bars? Could you hide your growing rage from family and friends? Could you gun the killer down as he left prison? Could you change your ID and leave behind your entire life - family, friends, jobs, house -and just disappear? Could Tim and Martha Foster do this? Forensic evidence...