One of several lawsuits filed by families of victims of the Sandy Hook Elementary School shooting in 2012 has been officially resolved.

The families of more than a dozen victims will split $1.5 million under recently finalized claims against the gunman's mother's estate. A lawyer for several victims' families says the settlements were finalized Dec. 17. Details of the agreements were first announced in August, and lawyers said at the time that the settlement had to be ratified by a probate court judge.

The lawsuits said Nancy Lanza failed to properly secure her legally owned Bushmaster AR-15 rifle. Her son, Adam Lanza, used the rifle to kill 20 first-graders and six educators at the Newtown school. He killed his mother before the school shooting and killed himself afterward.