Prosecutors announced the indictment against members of Thomas Matusiewicz's family Thursday afternoon.
Among those being indicted is the gunman's son, David Matusiewicz, who is set to be released next week from a federal detention center in New York after being accused of violating probation on federal fraud and kidnapping charges. Those charges stemmed from the 2007 abduction of his three daughters in a custody dispute with his ex-wife, Christine Belford.
Also indicted were Thomas Matusiewicz's wife, Lenore, and Lenore and Thomas' daughter and David's sister, Amy Gonzalez.
Thomas Matusiewicz shot and killed Belford and another woman on Feb. 11 before taking his own life.
