A man serving life in prison for molesting and murdering a young girl has died in prison. This as the girl’s mother fought to keep him behind bars.

It has been almost 50 years since Joan D’Alessandro’s case made headlines in New Jersey.

“It’s easy to talk about Joan because she was my personality,” says mother Rosemarie D’Alessandro.

The 7-year-old was killed on April 19, 1973. Rosemarie says that Joan left the house to deliver boxes of Girl Scout cookies.

“She said, ‘Goodbye mommy. I’ll be right back,’” Rosemarie says.

But minutes later Joan was molested and murdered by her neighbor Joseph McGowan. Joan’s body was found days later at a New York State Park.

McGowan, a science teacher, admitted to the crime and was sentenced to life in prison.

“She fought. She really fought,” says Rosemarie.

Rosemarie says that for years she had to fight to keep her daughter’s killer in prison, with another parole hearing just a few years away.

“It is – it’s torture. It’s torture,” she says.

But now that battle is over. The Bergen County Prosecutor’s Office confirms that McGowan died in prison on June 5.

“It was a certain shock of my body, but it was a good shock,” Rosemarie says. “There was some kind of, ‘Oh, this part is over.’”

Rosemarie worked for almost 30 years to make sure that McGowan lever left prison alive, creating a set of state child safety laws. Each of them is carved in stone at a Hillsdale memorial garden.

The Justice for Victim’s Law removes the statute of limitations on suing certain criminals do they don’t have money to appeal. Joan’s Law says that anyone who rapes and kills children under 14 will serve life without parole.

“I’m so thankful he didn’t make it out. So this way no other children, no other adults can lose their lives and suffer a lot, and that’s what I’m so thankful for,” Rosemarie says.

Joan’s Law did not apply to McGowan because it wasn’t retroactive. A federal version of the law was signed by President Bill Clinton in 1998.