The gorgeous 18-year-old's body was found in a huge pool of her own blood on the doorstep of her Chicago, IL home, by her father.
She was still holding the key.
At the time cops quickly honed in on former bouncer Michael Gargiulo who denied killing the youngster, although he admitted seeing her the day before.
And although her DNA was found under his fingernails, prosecutor's couldn't prove that it had come from anything more than casual contact, so their prime suspect was released without charge.
Sadly he went on to be charged with the 2001 murder of Ashley Ellerin, a 22-year-old Los Angeles fashion student who was stabbed to death in her home the day she planned to attend the Grammy Awards show with Ashton Kutcher.
Gargiulo also was charged in the 2005 fatal stabbing of a woman in El Monte, Calif., and with attempted murder in the 2008 stabbing of another Los Angeles woman.
But now after new witnesses came forward, he will finally be charged with the murder, cops suspected him of committing all those years ago.
One of those witnesses Temer Leary told the Chicago Sun Times he had decided to come forward after seeing Pacaccio’s distraught father when he was interviewed on “48 Hours.”
He said: “I watched the video of Tricia’s dad over and over. “What happened to that girl — to all of those girls — was terrible. No parent should have to go through that.”
Based on the two witness accounts, Gargiulo was charged Thursday in Cook County with first-degree murder in Pacaccio’s slaying.
He remains in California to face trial in the two killings there, but “will eventually be brought back to Illinois,” Cook County State’s Attorney Anita Alvarez said.