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The family of a young New Jersey woman raped and murdered in 1976 is fighting to keep her killer behind bars, after a quirk in state law has allowed him to “slip through the cracks” and appear before a parole board next month.

Kim Montelaro was 20 years old when she was abducted at knifepoint from a popular shopping mall and forced into woods near the Pine Lake Swim Club in Washington Township, N.J., where she was left to die after being raped and stabbed six times in her chest.

Her killer, Christopher Righetti, a then-16-year-old high school student from nearby River Vale, N.J., was convicted of murder in 1977 and sentenced to life in prison, though he has appeared before a parole board five times since 1991.

In his last hearing before the board in 2009, Righetti was declared ineligible for parole until 2022. But two bills passed in 2010, during a lame-duck session of the New Jersey state legislature, allowed for prisoners, such as Righetti, to receive a new parole hearing every three years. The state legislature later repealed the law, but the 52-year-old Righetti is still eligible to appear before the 15-member board as early as next month, three years after his last hearing, according to an official with the New Jersey State Parole Board.

“He slipped through the cracks,” the woman’s father, Tony Montelaro, told FoxNews.com from his home in Fort Myers, Fla.

Montelaro, who in 2009 traveled with his wife to the parole hearing in Trenton, has fought to keep Righetti – a prison powerlifter who officials claim tattooed the word “animal” on his body – from ever being released.

“He’s a monster and there’s no question he would do it again,” Montelaro said.

“Kim was beautiful. She smiled a lot, she was smart, she was personable. She would always fight for the underdog,” he said of his daughter, an honors student at the University of Rhode Island who was planning to attend law school. “We’ll never know what she could have become because her life was taken away from her for no reason,” he said.

Police say Montelaro was abducted on Aug. 31, 1976, as she got into her car parked outside the Paramus Park mall in Paramus, N.J., in broad daylight.

Township of Washington Police Chief Randy Ciocco, who was a young officer on patrol the day she disappeared, recalled spotting a suspicious vehicle parked at the Pine Lake Swim Club shortly before 3 p.m.

“I was turning around my car to check it out,” Ciocco said, “when I got a theft call,” forcing him to leave the scene. When Ciocco returned later that day, the car – later determined to be Montelaro’s – was gone.

Ciocco said a group of boys playing in woods near the swimming hole discovered Montelaro’s bloodied body the next day.

“There was every indication that she did not die right away,” said Ciocoo, who added that the knife used to kill Montelaro was later found in the mud.

New Jersey State Rep. Robert Schroeder, among other state and local lawmakers, is circulating a petition throughout northern New Jersey to keep Righetti behind bars.

“In my opinion, he will not be granted parole, but anything is possible and it’s unfortunate that we have to put the Montelaros through this every couple of years,” Schroeder,  a longtime resident of Washington Township, told FoxNews.com.

“It was a horrendous crime that affected the entire community,” he said. “He was an animal then and he’s an animal now.”