A young woman who accused Alexander Pacteau of subjecting her to a terrifying sex attack warned a government minister two years ago he would strike again.

The 21-year-old predator was left free to murder Irish nurse Karen Buckley after being cleared of the attempted rape and sexual assault.

Now his accuser has come forward to tell The Herald about how the ordeal has left her traumatised. She said: "I knew he would strike again."

In a case with striking similarities to that of occupational therapy student Ms Buckley, Pacteau was accused of attacking the young woman in a Glasgow lane in 2011.

He denied the offence and was cleared by majority verdict at court in Paisley in 2013.

The woman, who is now 28-years-old, met Pacteau by chance after a night out with friends in the city's Woodlands Road.

Just like Ms Buckley, Pacteau preyed on her trusting nature and struck up a conversation while they both waited for a taxi.

She said: "From the moment I knew he was found not guilty in my case, I knew in my heart I would see his name again one day because he had hurt someone else.

"When he was found not guilty my heart broke and I just didn't know how to recover.

"I had a horrible feeling I wouldn't be the last person that he hurt. And every day since that day this thought has tortured me."

She felt so strongly about Pacteau and the threat he posed to women that she wrote after her trial to the then Justice Secretary Kenny MacAskill warning authorities about him.

She said: "After the verdict, my world fell apart and I can’t describe the agony of not being believed.

"In desperation, I wrote a letter explaining why I knew he was a danger to others, which I sent to the Justice Secretary.

"In my last paragraph this is what I wrote: 'Please help me stop him from doing this or worse to another woman or girl. I dread to think what he may be capable of doing to others in the future. I cannot sit back and do nothing'.

"Reading this letter now makes me feel sick as my nightmare has come true."

Pacteau was alleged to have attacked her in a lane after she agreed to walk with him to try and get a taxi.

He was accused of forcing her to the ground, putting his hand over her mouth, carrying out a sex act and attempting to make her carry a sex act out on him.

Her ordeal only ended when people - including two men on a nearby balcony - heard her screams and rushed to her aid.

Pacteau was arrested a short time later.

The incident was alleged to have taken place in Baliol Lane, less than a mile from where Pacteau met Ms Buckley, on November 27 2011.

Earlier this week, the 6ft 4in former private schoolboy admitted murdering Karen by repeatedly clubbing her with a spanner, strangling her and dumping her in a barrel of caustic soda.

He is believed to have lured Ms Buckley, 24, into his car outside a Glasgow nightclub by offering her a lift home.

However, Pacteau drove to a secluded West End street and killed the Irish nurse within just 20 minutes of meeting her.

His first victim told how he attacked her within less than 10 minutes of meeting her.

"I've never witnessed anything like it," she said.

"He just suddenly changed. I said I needed to go to a cash machine for money and he just grabbed my arm and pulled me down.

"In a split second that kind stranger turned into a terrifying monster and the fear and terror I felt that night will forever haunt me."

In court Pacteau, claimed the victim had slapped him when he asked about her boyfriend and the pair fell over behind a car, with him on top of her.

Pacteau said as he fled the scene he was "confused". At one point, he even told jurors that he was gay.

The woman said: "The day I saw Alexander Pacteau's name in the paper in connection to Karen Buckley I felt someone had taken all the air from my lungs.

"My friend sent me a link to a story on my phone. When I read it, my legs just gave out.

"I have relived that night over and over, at how naive and trusting I was that this stranger was genuinely trying to help me get a taxi home."

She also told how she felt "lucky" she got away with her life after learning what Pacteau did to Karen.

"I never thought I'd say that", she added.

She also told how Pacteau punched the air and shouted "yes" when his not guilty plea was announced at the end of her trial.

The woman continued: "I am eternally grateful to every person who came to my aid and who appeared as a witness in my case.

"They helped give me my faith back and serve as a reminder that there are good people in this world.

"Even though I didn't get the verdict I deserved, I still would have done it all again.

"I've carried the nightmare of that night in my mind for almost four years and I would appreciate being left alone now so I don't have to relive it anymore.

"I've accepted that I won't get justice, but I believe when he is sentenced, in a strange way, that will be my justice.

"These past few months have been very hard. I feel selfish even uttering such words because it is nothing compared to the pain and suffering of Karen Buckley's family.

"My heart breaks for them. I want to tell them how truly sorry I am and I hope she gets the justice she deserves."

A Scottish Government Spokesman said: “Mr MacAskill’s office responded at the time, expressing sympathy to the woman involved, but also making clear that the independence of Scotland’s judiciary is a fundamental part of our legal system and Ministers cannot intervene in individual cases.

“Decisions on prosecution are not a matter for the Scottish Government but are solely for the Lord Advocate and the Crown Office.”