Thirteen law professors who specialize in common law torts have thrown their weight behind a negligent entrustment claim lodged against the makers of the AR-15 rifle used in the Sandy Hook school shooting.

Their 35-page amicus brief filed with the Connecticut Supreme Court Monday focuses on how negligent entrustment should apply to Remington and Bushmaster Firearms, the makers of the AR-15 rifle used in the massacre. The brief was submitted in an appeal to the state Supreme Court filed by attorneys representing some of the families of educators and children killed.

The professors are tort law experts from universities including Stanford, Yale, Brooklyn Law School and the University of Connecticut School of Law.

While a state Superior Court previously ruled negligent entrustment doesn’t apply in this case, the professors claim the “flexible tort has been applied to a range of domains, including firearms.”

The brief’s co-author, Stanford law professor Nora Freeman Engstrom, said negligent entrustment boils down to one question. “That is, did the defendant take adequate precautions given the magnitude of the foreseeable risk? And, here, the jury might ultimately find the defendant failed to take adequate precautions in their sale of military grade assault weapons to an untrained civilian population.”

Negligent entrustment occurs when a party provides a product to another party knowing the receiving party may injure someone.

Attorneys for the family claim Remington, which sold the Bushmaster AR-15 used by Adam Lanza, knew or should have known the weapon was meant for war but was going to untrained civilians.

Lanza’s December 2012 shooting spree at the Sandy Hook Elementary School lasted about five minutes. Lanza fired 154 bullets in that time, killing more than two dozen people and injuring several others.