Hugh McQuaid file photo

(Updated at 12:48 p.m.) Families of nine people killed at Sandy Hook Elementary School and one survivor are suing Bushmaster Firearms, the company that manufactured the weapon used in the incident, as well as the weapon’s distributor and seller.

The lawsuit, which claims wrongful death and negligence, is being filed by the law firm Koskoff, Koskoff & Bieder. It is dated Saturday, Dec. 13, 2014, the day before the second anniversary of the shooting.

According to the complaint, the AR-15 rifle used by gunman Adam Lanza to kill 26 people on Dec. 14, 2012, at Sandy Hook Elementary School in Newtown was designed for military use and should have never been “entrusted” to the general public. Before his rampage at the school, Lanza killed his mother at their home and he killed himself as police arrived at the school.

“This weapon was not designed for home defense or hunting. This weapon was designed to efficiently kill other human beings in combat,” Josh Koskoff, an attorney for the families, said in a press release.

“The AR-15, however, has little utility for legitimate civilian purposes,” the lawsuit states. “The rifle’s size and overwhelming firepower, so well adapted for the battlefield, are in fact liabilities in home defense.”

The lawsuit claims that military and law enforcement personnel who use similar weapons have specialized training and strict safety requirements. “When AR-15s are entrusted to the public there is no institutional structure in place to oversee the safe and intelligent use of those weapons,” the complaint reads.

Two plaintiffs to the complaint, Nicole Hockley, whose son Dylan was killed during the shooting, and Mark Barden, whose son Daniel was killed, declined to comment on the lawsuit at a Monday press conference to mark the second anniversary of the shooting.

In a statement, the National Shooting Sports Foundation, a firearm industry trade organization, pointed to a law passed by Congress in 2005 that was designed to protect gun sellers and manufacturers from negligence lawsuits. The foundation said the complaint by the Sandy Hook families lacked legal merit.

“The U.S. Congress with overwhelming bipartisan support passed the Protection of Lawful Commerce in Firearms Act in 2005 in order to prevent lawsuits that seek to blame manufacturers for the criminal misuse of products that were lawfully sold. Like all Americans, we have great sympathy for the families represented in this suit. This tragedy was caused by the criminal actions of a mentally unstable individual,” the statement said.

U.S. Sen. Richard Blumenthal, who attended the press conference with Hockley and Barden, suggested the families may have decided to bring the lawsuit because they were frustrated that Congress has not adopted stricter gun regulations in the two years since the shooting.

But Blumenthal, who served for two decades as the Attorney General of Connecticut, declined to comment on the merits of the lawsuit or whether it would be pre-empted by the 2005 law.

The families’ “contention is they’re not barred by any existing law from bringing that lawsuit,” he said. Blumenthal added that he had not yet read the complaint.

“I want to see the particular allegations of the lawsuit to know how strong the legal merits are. But I will say, these claims are serious. They deserve a serious day in court as does any lawsuit by people who have suffered this kind of deep, enduring injury, and harm,” Blumenthal said.

The plaintiffs involved in the lawsuit are the families of Victoria Soto, Dylan Hockley, Mary Joy Sherlach, Noah Pozner, Lauren Rousseau, Benjamin Wheeler, Jesse McCord Lewis, Daniel Barden, and Rachel D’Avino, as well as Natalie Hammond, a teacher who was injured during the shooting.

They are suing Bushmaster Firearms, the manufacturer, Camfour Inc., a distributor, and Riverview Sales, a gun store in East Windsor that has since closed.