PHILADELPHIA (CBS) — Experts still can’t agree if the death of a teacher in her Manayunk apartment nine years ago was a suicide or a homicide. Ellen Greenberg’s family is fighting for answers and new evidence is being shared exclusively with Eyewitness News.

The Greenberg family’s long struggle is headed to trial. Her family is pushing the Philadelphia Medical Examiner’s Office to change their daughter’s death certificate from suicide to homicide. They say new medical technology is offering new clues.

“This is a homicide case and it’s indefensible as suicide,” attorney Joe Podraza said.

Podraza is set to face off with the Medical Examiner’s Office in court over Greenberg’s mysterious death.

“This is an only child who was very close with her parents,” Podraza said.

In January 2011, Greenberg was a 27-year-old teacher living in Manayunk with her whole life in front of her. She was found dead with 20 stab wounds to her body inside her apartment at the Venice Lofts.

The Philadelphia Medical Examiner’s Office initially ruled it a homicide but changed it to suicide months later.

The Greenberg family never bought that their daughter killed herself.

Podraza is using a technology called photogrammetry to prove the case is a homicide.

Greenberg’s legal team recreated her anatomical and physiological attributes, showing it would be impossible for Greenberg to stab herself multiple times in the back of her head. One of the wounds was so deep it would have paralyzed her.

“Which means she couldn’t have completed the remaining wounds,” Podraza explained.

Podraza said this is very powerful evidence.

“I think it’s so powerful that it’s clear to me that there’s a murderer walking among us, or murderers, and that’s frightening from my vantage point,” he said.

Something else that was unusual with Greenberg’s death is her body was found sitting on the floor, propped up against the kitchen cabinets. The blood splatter on her body should have flowed vertically, but veteran law enforcement officer Tom Brennan says it didn’t.

“You see it flowing horizontally, which meant to me the victim was in a different position for a significant amount of the time,” Brennan said.

The trial to determine if Greenberg’s manner of death should be changed from suicide to homicide is expected to begin next year.