HARTFORD, Conn. — The father of a victim of the Sandy Hook Elementary School massacre has won a defamation lawsuit against the authors of a book that claimed the shooting never happened — the latest victory for victims' relatives who have been taking a more aggressive stance against conspiracy theorists.

The book, "Nobody Died at Sandy Hook," has also been pulled from shelves to settle claims against its publisher filed by Lenny Pozner, whose 6-year-old son Noah was killed in the shooting.

"My face-to-face interactions with Mr. Pozner have led me to believe that Mr. Pozner is telling the truth about the death of his son," Dave Gahary, the principal officer at publisher Moon Rock Books, said Monday. "I extend my most heartfelt and sincere apology to the Pozner family."

Lenny Pozner, father of Newtown victim Noah Pozner, 6. Facebook, Lenny Pozner

A Wisconsin judge issued a summary judgment Monday against authors James Fetzer and Mike Palacek, a ruling that was separate from the settlement between Pozner and the book's publisher. A trial to decide damages has been set for October.

Pozner has been pushing back for years against hoaxers who have harassed him, subjected him to death threats and claimed that he was an actor and his son never existed. He has spent years getting Facebook and others to remove conspiracy videos and set up a website to debunk conspiracy theories.

Lately, the fight has been joined by others who lost relatives in the Dec. 14, 2012, school shooting in Newtown, Connecticut. After quietly enduring harassment and ridiculous assertions for years, some have changed their approach, deciding the only way to stop it is to confront it. Their efforts have turned the tables on the hoaxers, including Alex Jones, host of the conspiracy-driven Infowars website.

Robbie Parker, whose 6-year-old daughter Emilie was among 20 first-graders and six educators killed at Sandy Hook, spent years ignoring people who called him a crisis actor. His family moved to the West Coast, but still the harassment didn't stop. He would get letters from people who found his address. He was once stopped in a parking garage by a man who berated him and said the shooting never happened.

"You are taught when you are young that you ignore bullies and eventually they will leave you alone," Parker said. "But as time went on, and my other girls were getting older, I realized they weren't stopping and some of this was getting worse and getting more personal."

Parker is now part of a lawsuit against Jones, has testified before Congress and pushed for changes on social media platforms, such as YouTube, which announced this month it will prohibit videos that deny the Sandy Hook shooting and other "well-documented events."

"It wasn't until the lawsuits and until it became a mainstream news story that people realized they were being complicit in this and started to moderate the content," Parker said.

Pozner is the lead plaintiff in several of at least nine cases filed against Sandy Hook deniers in federal and state courts in Connecticut, Florida, Texas and Wisconsin.

In the case against Jones, the families of eight victims and a first responder say they've been subjected to harassment and death threats from his followers. A Connecticut judge ruled in the defamation case that Jones must undergo a sworn deposition, which is scheduled for July in Texas.

Wisconsin's Dane County Circuit Judge Frank Remington ruled Monday that Pozner had been defamed by Fetzer and Palacek, whose book claimed, among other things, that Noah's death certificate had been faked, according to Pozner's lawyer, Jake Zimmerman.

"If Mr. Fetzer wants to believe that Sandy Hook never happened and that we are all crisis actors, even that my son never existed, he has the right to be wrong. But he doesn't have the right to broadcast those beliefs if they defame me or harass me," Pozner said. "He doesn't have the right to use my baby's image or our name as a marketing ploy to raise donations or sell his products. He doesn't have the right to convince others to hunt my family."

Before the case went to a judge, Fetzer had said "evidence clearly shows this wasn't a massacre, it was a FEMA drill," referring to the Federal Emergency Management Agency.

"If you believe otherwise, then you are being played," Fetzer said at the time.

A redacted copy of the actual death certificate is attached to Pozner's lawsuit. Additionally, Pozner has had DNA samples taken and compared with those provided by the Connecticut medical examiner to prove that Noah was his son. He has put Noah's birth certificate, report cards and medical records into the public file in his legal actions.

His goal, he says, is to make sure that "normal people" have access to the truth and aren't persuaded by the hoaxers.

A Florida woman, Lucy Richards, was sentenced to five months in prison for sending Pozner death threats. She was also banned from visiting web sites run by conspiracy theorists, including Fetzer.

Christopher Mattei, a lawyer who represents the families in their Connecticut lawsuit against Jones, said his clients want to live their lives free from that kind of harassment. They also want these hoaxers to know they are affecting real people, who have already been emotionally devastated.

"When the grief process includes having to justify your grief or having to prove your child's existence," he said, "it makes it very difficult."