West Yorkshire, England: A woman forced to watch an ex-boyfriend murder her sister and best friend in a jealous rage has told how she still has nightmares every night.

Elisa Frank was just 19 when Ahmad Otak stabbed her 17-year-old sister Kimberley 15 times in their flat in Wakefield, West Yorkshire, before standing over her body laughing.

He then licked the knife clean of blood, spat on her, tied Elisa up with electrical flex and made her watch as he stabbed and slashed 18-year-old Samantha Sykes 34 times.

Then aged 21, the domestic abuser abducted Elisa and drove to Dover in a failed bid to escape the country, but was arrested and jailed for life with a minimum of 34 years.

Nearly three years after the horror attack in March 2012, it still haunts Elisa's dreams

Her sister often appears to her as a ghost and she says writing about the experience is the only way she gets through.

"If I didn't have writing to focus on I would be lost," she said.

"It's all I do. It's something I use to get through.

"I still have nightmares every single night. It started out being about the event, then sometimes I'd see Kim as a ghost.

"I try not to think about it during the day. If I do, it's too overwhelming."

The double murders happened a month after Elisa broke up with Otak, who had groomed her while she lived in a children's home after he arrived in Britain as an asylum seeker from Afghanistan.

The two had been in a turbulent relationship and Otak threatened to kill Elisa if she left him.

“He started making up weird rules,” she told the Mirror last year. “One day he told me I wasn’t allowed to talk to men any more. I wasn’t allowed to drink either because it wasn’t allowed in his culture.

“Then he stopped me from seeing certain girls he said were a ‘bad influence’.

“Tiny things would set him off. If he caught me watching soaps he would beat me because he thought the way women behaved in them was disgusting.

“I realised he was crazy and I wanted to leave him but I had nowhere to go. I was trapped.”

Brave Elisa spent several months in hospital after the attack and was diagnosed with post-traumatic stress disorder and a borderline personality disorder.

Now, however, she is recovering and has written a 50,000-word account of her experience called The Borderline Diaries - a title taken from her diagnosis.

She said the prospect of speaking publicly about her grief was frightening, but said: "Me and my sister used to write a lot. We used to talk about getting published, so I feel like this is for her.

"When you write about someone, it keeps their memory alive."

Elisa addresses her sister directly in the book, questioning why it was Kim had to die instead of her.

"Just come back please," she writes. "Come back and I'll make it all better and for once in my life I will help someone else, you and Sammy.

"I need you here and I'll wrap Band Aids around your wounds, for they should have been mine.

"I know I have not been there for you over this past year. I know I have failed you as a sister and a best friend.

"I'm sorry for all those times you came round to the house of horrors and I didn't answer. I pretended there was nobody in.

"I'll write again soon and I won't stop writing until you are returned to me.

"Promise me one thing? One day you will come back to me, but don't wait too long.

"I love you forever and always. Me and you... twins for life, right? Distance never kept us apart before."