Parents of victims will argue against death penalty for killing Tsarnaev . The year - old boy was youngest of victims in the 2001 Marathon attacks . Sentencing punishment for Tsarnaev begins next week .
Parents of Martin Richard argue against death penalty for Dzhokhar Tsarnaev . The 8-year-old boy was youngest of victims in the Boston Marathon bombings . Sentencing phase for Tsarnaev begins next week .