Ellen Greenberg, a 27-year-old first-grade teacher in Philadelphia, and her longtime boyfriend, Sam Goldberg, had just sent out "save the date" cards for their upcoming wedding.

As a blizzard approached Philadelphia, her school dismissed early. At home with her fiancé, Sam left around 4:45 p.m. to work out at the apartment complex gym. Less than an hour later, when he returned, the door was locked from the inside.

For over 20 minutes, Sam pounded on the door, texted, and called Ellen, but received no response. At 6:33 p.m., he broke down the door and found Ellen on the kitchen floor, stabbed 20 times in the chest, neck, and head. While on the phone with 911, Sam was instructed to perform CPR, but he told them a knife was still lodged in her chest. First responders arrived within minutes, and Ellen was pronounced dead at 6:40 p.m.

Police launched an investigation. Initially, the medical examiner ruled Ellen's death a homicide, but after meeting with police, the ruling was changed to suicide. Since the medical examiner changed the manner of death, Ellen’s parents, Josh and Sandee Greenberg, have been fighting to have the ruling reversed.

Now, Guy D'Andrea, a former assistant district attorney who worked on the case, is speaking out. 

Joining Nancy Grace today: 

• Sandee & Josh Greenberg -  Ellen Greenberg's Parents, Twitter: @justice4ellentw, Facebook: @justice4ellenFB,   Facebook: #Justice For Ellen
• Guy D’Andrea  - Former Pennsylvania Prosecutor, Attorney at Laffey Bucci D’Andrea Reich & Ryan
• John Luciew [pronounced Lucy]- (Harrisburg, Pa) Journalist for PennLive.com and The Patriot-News of Harrisburg, Pa. (specializes in true crime and cold case investigations for PennLive.com); Author: “Kill the Story;” Twitter: @JohnLuciew 
• Benee Knauer - Author of "What Happened To Ellen?: An American Miscarriage of Justice" 
• Tom Brennan – Private Investigator and Consultant for the Greenbergs
• Dr. Kendall Crowns – Chief Medical Examiner Tarrant County (Ft Worth) and Lecturer: University of Texas Austin and Texas Christian University Medical School