DOVER, Del. (CBS/AP) — Federal prosecutors said Thursday that they have filed stalking crime charges against three relatives of a gunman who killed two women at a Delaware courthouse before taking his own life.

Prosecutors scheduled a news conference Thursday afternoon to announce an indictment against members of Thomas Matusiewicz’s family.

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 City. Matusiewicz, 46, was taken into custody after the Feb. 11 shooting and sentenced to six months in federal prison for violating probation on kidnapping and fraud charges. Those charges stemmed from the 2007 abduction of his three daughters in a custody dispute with his ex-wife, Christine Belford.

Thomas Matusiewicz, 68, shot Belford, 39, and her friend Laura Mulford, 47, after they arrived at the courthouse for a child support hearing. He then took his own life after exchanging gunfire with police.

Immediately after the shooting, authorities in Texas, where the gunman lived, suggested in a search warrant affidavit that Thomas Matusiewicz; his wife, Lenore; and his son were all suspected of “intentionally and knowingly participating in a murder.”

Lenore Matusiewicz and Amy Gonzalez, Lenore’s daughter and David’s sister, also were indicted Thursday.

The four-count indictment lists the charges as conspiracy, two counts of interstate stalking and cyberstalking.

David Matusiewicz later told his family in an email obtained by The Associated Press that officials apparently were trying to build a case against him.

David Matusiewicz, who pleaded guilty in 2009 to fraud and kidnapping after taking his three daughters to Central America in 2007, was released from prison last year.

Lenore Matusiewicz, 68, served more than a year in Delaware state prison for endangering the welfare of her three granddaughters after helping her son take them to Central America.

After the courthouse shooting, federal prosecutors alleged that David Matusiewicz had repeatedly failed to abide by the conditions of his probation, including a prohibition against being around firearms. Investigators found several guns in and around the Texas house he shared with his parents. Prosecutors alleged that Matusiewicz knew that his father, whom probation officers described as “perpetually armed,” brought guns with him on the trip from Texas to Delaware for the child support hearing.

Federal prosecutors initially alleged that Matusiewicz violated his probation by not properly disclosing his whereabouts and not paying court-ordered child support and restitution. They said that Matusiewicz, in receiving permission to travel to Delaware for a hearing on his request for a reduction in child support obligations, said he would be staying with an uncle in Bayville, N.J., and that he failed to disclose that he spent the night before the shooting at a friend’s home in Elkton, Md.

Lenore Matusiewicz said the family left her brother’s home in New Jersey and spent the night in Elkton because there was a threat of bad weather and they wanted to be closer to the Wilmington courthouse.

Prosecutors later revised the probation violation charges, saying David Matusiewicz violated prohibitions against having guns or ammunition. Authorities executing a search warrant at his parents’ Texas home the day after the courthouse shooting found ammunition and guns inside the home, in a recreational vehicle parked just outside the home, and in a storage shed.

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed. The Associated Press contributed to this report.)

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