The district attorney of Middlesex County in Massachusetts will prosecute admitted Boston Marathon bomber Dzhokhar Tsarnaev for the killing of MIT police officer Sean Collier, her office announced today.* Tsarnaev is currently being tried on 30 federal charges related to the bombing and to Collier’s killing—and his defense team has already admitted he is guilty, apparently hoping only to convince the jury to sentence him to life in prison rather than condemning him to death. But Tsarnaev is not charged at the federal level with murder; rather, he’s charged with crimes such as “Conspiracy to Use A Weapon Of Mass Destruction Resulting in Death.” Collier’s slaying falls to Middlesex County to prosecute.
If Middlesex County is prosecuting Tsarnaev for Collier’s killing, you might ask, why isn’t Suffolk County prosecuting Tsarnaev for the deaths of the three bombing victims who died in that jurisdiction? The answer appears to be that Suffolk District Attorney Daniel Conley believes that the federal bombing charges deal directly enough with the killings of the three marathon victims that Tsarnaev’s convictions on those counts would provide substantial justice for their deaths. Collier’s death, by contrast, took place days after and in a different location from the marathon bombing and is addressed in the federal indictment with more peripheral charges such as firearms possession.
*Correction, March 19, 2015: This post originally misspelled Dzhokhar Tsarnaev's name.