The Obama administration is pursuing new charges against four former operatives of the private military firm Blackwater for the 2007 Nisoor Square massacre that killed 17 Iraqi civilians, including women and children. An appeals court reinstated the case two years ago after a lower court dismissed it in 2009. Now a federal grand jury has issued a new indictment charging the men with voluntary manslaughter and other crimes. In a statement, the chief government prosecutor said, “these defendants abused their power through a relentless attack on unarmed civilians that recklessly exceeded any possible justification.” A hearing is set for next week.