Judge Esther Salas speaks about law named after her son, killed by gunman targeting her

Federal judge Esther Salas has been motivated by the memory of her son to fight for a new state law to protect public officials after her only child was murdered by a gunman at her family's home this summer.

Salas, 51, and her husband, Mark Anderl, had been celebrating the 20th birthday of their son, Daniel, when he was killed on July 19 by a gunman posing as a delivery driver. The man came to the front door of their New Jersey home, rang the doorbell and then shot Daniel to death. He also shot Salas' husband three times.

That tragic day fueled Salas to push for "Daniel's Law," a new law signed by New Jersey Gov. Phil Murphy on Nov. 20 that makes it a crime to publish the personal information of New Jersey judges, prosecutors and law enforcement officers, including their phone numbers and home addresses.

"I would want people to know about my Daniel that he always put others before himself, and that's why I know he would want me to do what I'm doing now because he would want others to be protected," Salas told Savannah Guthrie on TODAY Monday.

"I know that Daniel's looking down and saying, 'Mom, keep it going, keep it going because we need to make sure that everyone is safe.'"

The gunman, a self-described "anti-feminist lawyer" named Roy Den Hollander, was found dead with a self-inflicted gunshot wound just hours after the attack. Den Hollander once appeared in front of Salas in court and had compiled personal information on her, authorities said.

Salas' husband survived the attack after she said her son took a bullet to the chest to protect him.

"The center of our universe"

"He was, for us, our life," Salas said. "He was the center of our universe, and we were the center of his universe, and I think that's why it wasn't even a question of what he was going to do, he was going to protect his dad. He was going to protect me.

"Daniel was goodness, and he was joy, and he was love, and those are the things that I hold onto, that I have to believe and I have to continue to strive to be better for his sake, to honor his legacy, to make him proud. I want him to always be proud of his mother and father."

Anderl is still recovering from his injuries suffered in the attack, Salas told TODAY.

"Regrettably, Mark has had a medical setback," Salas said. "He's gonna need surgery in the very near future. So he is still battling those injuries, and obviously battling the injury to his heart, so we are just day by day, taking it second by second."

The couple also will be holding their first Thanksgiving without their son.

"You know what, I am holding it together because I know that's what Daniel would want me to do, and I have a tremendous amount of faith, and I rely and lean on that faith and lean on my loved ones to get me through this difficult time in our lives," Salas said.

Salas is now pushing to expand Daniel's Law beyond New Jersey. She wants laws to enhance U.S. Marshal services and security at courthouses in addition to protecting the private information of judges.

"What I'm hoping will happen now is we will expand these protections nationwide," she said. "These things need to happen, because as I have said over and over again, this is a matter of life or death. And for us, Daniel's death should be a reminder of what will happen if we don't do things and we don't do them immediately."

An earlier version of this story was first published on TODAY.com.

Follow NBC Latino on Facebook, Twitter and Instagram.