LONDON — The British student Meredith Kercher has been all but forgotten in the sensational case that has seen American Amanda Knox and her former Italian boyfriend Raffaele Sollecito convicted, spend time in jail, cleared, then found guilty again of her murder, her family says.

"Mez has been forgotten in all of this. The media photos aren't really of her. There's not a lot about what actually happened in the beginning. So it is very difficult to keep her memory alive in all of this," Stephanie Kercher, Meredith's sister, says in a BBC documentary that is set to be broadcast Monday evening in the United Kingdom.

USA TODAY has viewed the documentary — called "Is Amanda Knox Guilty?" — in advance of its release at 9 p.m. local time (4 p.m. ET).

"Everything that Meredith must have felt that night. Everything she went through. The fear and the terror and not knowing why. She didn't deserve that. No one deserves that," Stephanie Kercher says in the documentary, which features interviews with lawyers and experts from members of both the prosecution and defense teams.

In part, the documentary attempts to address some of the Kercher family's frustration at a case that has dragged on for six years with many dramatic reversals of fortune, and that has brought headline after headline for Knox and Sollecito, but little in the way of justice for the 21-year-old who was found partially clothed in a pool of blood in the house she shared with Knox in Italy.

"Anybody losing anyone close is hard, losing someone so young and the way we did is obviously 100 times worse, and on top of that to have all the media attention that has gone for so long makes it very difficult to cope with," Lyle Kercher, Meredith's brother, says in "Is Amanda Knox Guilty?"

Meredith Kercher was found strangled and stabbed around 40 times on Nov. 2, 2007. Ivory Coast native Rudy Guede was convicted of Meredith's murder in October 2008 and was sentenced to 30 years in prison but the judge found that he did not act alone.

Knox, who currently resides in Seattle, and Sollecito, who has remained in Italy, were also convicted in 2009 of her murder but that was overturned on appeal in 2011. Last month, they pair were again convicted and sentenced to 28.5 years and 25 years in prison, respectively. They say they will now appeal this latest decision before Italy's highest court.

"She was very excited about coming to Italy, looking forward to learning about Italian culture. Seeing the city of Perugia and making new friends. She really fought to be here. She wanted to be here," Stephanie Kercher says in the BBC documentary, reflecting on her sister's decision to study in Italy.

"We were just talking on the sofa and having a little cuddle of goodbye and I just remember her suddenly crying and saying that she was going to be sad to go but she was excited to come and I remember being quite taken aback and I thought, 'Don't make me sad. I'll miss you but you'll go and have fun.'"