Adam Lanza was able to purchase the weapon he used to commit the 2012 Sandy Hook massacre legally.

The maker of the assault rifle used in the 2012 massacre of more than two dozen students and teachers at Sandy Hook Elementary School was ordered to allow its executives to be questioned ahead of a trial of a lawsuit by victims' families, pushing the case further than most such suits have reached.

Connecticut State Judge Barbara Bellis on Tuesday set a trial for April 3, 2018, "marking another major victory for families of the victims in their effort to hold gun companies responsible" for the 2012 school shooting, their law firm, Koskoff Koskoff & Bieder PC, said in a statement.

The families claim Bushmaster Firearms International LLC, a unit of Cerberus Capital Management LP's Remington Arms Co., engineered the rifle specifically for the US military to kill in combat and is being wrongfully sold to civilians to make a profit. In a ruling last week, Bellis denied a request to toss the case on the grounds that it was automatically blocked by a 2005 federal law shielding gunmakers from liability in most cases.

Adam Lanza Lanza, 20, shot and killed his 52-year-old mother, Nancy, before going to the school and killing 20 children and six adults.

The rulings are renewing focus on US gun violence as Hillary Clinton and Bernie Sanders, the two Democratic presidential hopefuls, clash over the issue. Clinton has repeatedly criticised Sanders over his support for the 2005 shield law, called the Protection of Lawful Commerce in Arms Act.

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Jessica Kallum, a spokeswoman for Madison, North Carolina-based Remington, didn't immediately reply to a message seeking comment on the ruling.

National Debate

The 2012 attack by Adam Lanza reignited the national debate over gun violence and spurred calls for lawmakers to strengthen firearm-control laws, such as expanded background checks on buyers, a ban on civilian sales of military-style rifles and a limit on the ammunition capacity of magazines. Those efforts have mostly failed, leading President Barack Obama to seek change through executive action, though such measures are minor by comparison.

Last week's ruling didn't address the merits of the families' claims, focusing instead on whether the court had jurisdiction, given federal and state laws.

The US Supreme Court in 2009 left intact lower court decisions shielding Smith & Wesson Holding Corp., Sturm, Ruger & Co. and other gunmakers from suits pressed by New York City and shooting victims in Washington, D.C. The justices, without comment, rejected appeals that challenged the constitutionality of the 2005 federal law.

Legally Purchased

Lanza, 20, shot and killed his 52-year-old mother, Nancy, before going to the school and killing 20 children and six adults. Lanza killed himself after the massacre with a Glock pistol. The suit was filed by one survivor and the families of four adults and five children who died. The rifle used in the killings had been legally purchased by Nancy Lanza.

According to the complaint, the size and firepower of the rifle used by Lanza are "liabilities in home defense," and there is one "tragically predictable civilian activity" in which it succeeds -- mass shootings.