The families of victims in the 2012 shooting at Sandy Hook Elementary School must receive access to internal documents at Infowars, the internet and radio show whose host, Alex Jones, has spread the false claim that the shooting was an elaborate hoax, a judge ruled on Friday.

The ruling was a legal victory for the families, which filed a defamation lawsuit against Mr. Jones, who traffics in conspiracy theories, and Infowars last year. The suit argued that peddling bogus stories was essential to the business model of Infowars, which sells products including survivalist gear, gun paraphernalia and dietary supplements.

A gunman killed 20 children and six adults in the Sandy Hook shooting in Newtown, Conn., just over six years ago, and Mr. Jones helped to spread the idea that grieving relatives of those victims were paid “crisis actors.”

The plaintiffs in the lawsuit are relatives of five children and three adults who were killed, and one F.B.I. agent who responded to the shooting. Their complaint said the families have faced “physical confrontation and harassment, death threats, and a sustained barrage of harassment and verbal assault on social media.”