Like most identical twins, the Spahalski brothers have a lot in common... but they may be the only identical twins who have both separately committed murder. Cuomo meets face-to-face with Robert Spahalkski inside a maximum-security prison where he's serving 100 years to life for four murders. The host confronts him with details of his crimes and tries to glean insight into the cause of his murderous urges. Could the desire to kill be a genetic trait? Cuomo tries to find some answers to the age-old question of nature versus nurture.