HARTFORD, Conn. — The state Supreme Court on Monday overturned a $12 million jury verdict against the Boy Scouts of America — the largest ever against the organization — in the case of a boy who said he was sexually assaulted by an older boy in his troop in the mid-1970s.

Justices ordered a new trial in a split decision, saying the trial judge improperly denied a defense request to instruct jurors on negligence liability. Three of the seven justices said they believed the case should have been dismissed because of a two-year statute of limitations on lawsuits alleging negligence and recklessness.

The plaintiff, identified as John Doe in court documents, sued the Irving, Texas-based Boy Scouts in 2012. He said he was sexually assaulted three times beginning when he was 11 by an older Scout in Troop 137 in New Fairfield. He said the abuse sent his life into a downward spiral of suicide attempts, drug abuse and an inability to be intimate with people.

Doe’s lawsuit said national Boy Scouts leaders failed to protect him. He said leaders knew for decades about child sexual abuse during scouting activities, including many instances of older Scouts sexually assaulting younger Scouts, but didn’t act to prevent it.

Doe’s lawyers, Paul Slager and Jennifer Goldstein, presented evidence introduced at similar trials across the country — that Boy Scouts officials kept confidential files dating to the 1920s that contained information on people suspected of being pedophiles.

“Rather than use this information to implement basic policies to prevent further sexual molestations, however, BSA … concealed the information from local councils, local troops, parents and scouts themselves,” Slager and Goldstein wrote in a legal brief. “BSA placed its reputation above the well-being of its youth members for decades, resulting directly in the preventable sexual victimization of thousands of young boys, including plaintiff.”

Slager said he and Goldstein were disappointed with the Supreme Court’s ruling but respected it.

The Boy Scouts of America said it was pleased the court overturned the jury verdict and was reviewing its opinions in the case. It said the episodes alleged by Doe “run counter to everything” it stands for.

“Youth protection is of paramount importance to the Boy Scouts of America and our organization has always focused on the best interests of our youth,” it said in an emailed statement. “In the nearly 40 years since these events took place we have continued to develop and enhance our efforts to protect youth, regularly consulting with experts from law enforcement, child safety, psychology, and other disciplines to ensure our efforts consistently evolve along with the ever-changing awareness of the dangers and challenges facing youth.”

Officials with the Boy Scouts said previously that they disagreed with the jury’s findings and noted the Scouts now have many measures in place to prevent abuse, including criminal background checks, mandatory reporting of abuse allegations and a comprehensive education program.

A jury in Waterbury Superior Court found in Doe’s favor in December 2014 and awarded $7 million in damages, and a judge added nearly $5 million. The verdict included compensatory and punitive damages for negligence, infliction of emotional distress and recklessness.

The Supreme Court on Monday also rejected claims by the Boy Scouts that the organization had no “duty” to protect Doe from the older Scout’s actions and that Doe didn’t present sufficient evidence that the Boy Scouts were responsible for what happened to him.

The older Scout accused of abusing Doe was identified in court documents as Siegfried Hepp, who was a Boy Scout leader for two decades before being charged in 2000 with fondling a 15-year-old boy. Hepp pleaded guilty to risk of injury to a minor and was sentenced to 20 years of probation and 10 years of sex offender registration. He wasn’t a defendant in Doe’s lawsuit.

Messages seeking comment were left with phone listings for Hepp on Monday.