Melissa Mahon imagined she was Cleopatra reincarnated. And the heavily tattooed middle-aged man she was infatuated with had similarities to Mark Anthony, Cleopatra's lover. The pair were destined to run away together and start a new life but would meet a tragic end. After they died, the 14-year-old confided to friends, they would be burned on a boat together.

But in reality, only one of them died. And the man Melissa believed would be her saviour is now standing trial for her murder.

It wasn't the only fantasy Melissa harboured about 44-year-old Ronnie McManus, referred to in court as Ronnie Dunbar. She told people he was her father and confessed to his girlfriend shortly before she disappeared that she had been in love with him in the past, but now simply loved him like a daughter should.

Dunbar cuts an unlikely figure of fascination for a 14-year-old girl. His arms, neck and face are tattooed and at first glance he's a man no one would dare mess with. His head is shaven and his physique is that of a once keen body-builder who has let his training slip. He sits in court number two at the Central Criminal Court with an air of indifference.

He chats easily with his legal team and has relaxed into his surroundings; this courtroom will be his home for the next four weeks. No family or friends have come to support him.

Melissa's parents, Freddie and Mary, sit quietly in the courtroom absorbing the appalling details of their daughter's short life while Dunbar, their neighbour whom they know well, steals furtive glances in their direction.

Melissa was a lonely and troubled child. The youngest of 10 children, her home life was chaotic. She accused her father of sexual abuse and her mother of beating her. The only person she seemed to trust was Ronnie Dunbar, the father of her close friend Samantha. Dunbar claims the teenager became so infatuated with him that at one stage he barred her from his home. But his ex-girlfriend, Angelique Sheridan, tells a different story. She told the court one of his daughters told her Melissa said she was pregnant by Dunbar. And he planned to strangle her to death rather than face jail for having sex with the child.

Dunbar, of Rathbraughan Park, Sligo, denies killing Melissa between 14 and 30 September 2006, and threatening to kill his own daughter. The teenager's skeletal remains were found on the shores of Lough Gill in February 2008, 15 months after she went missing.

Melissa was a frequent runaway, often sneaking out of the living room window of her home in the Rathbraughan estate to call down to the Dunbars' house a few minutes' walk away. Because she was missing so much school, the HSE got involved in March 2006. By August of that year, social worker Catherine Farrelly learned that Melissa's family hadn't seen or heard from her in over two weeks. Melissa's mother didn't seem too concerned about her young daughter. She was probably just hanging around the Dunbars' house and would come home in her own good time, she told the social worker.

'Hurt and frightened'

But this wasn't good enough for social services. Farrelly called to Dunbar's house after going with Melissa's mother to the garda station in Sligo. Ronnie Dunbar was there and told her he had no idea where Melissa was. He said he was worried about her and would make inquiries to see if she could be found. Farrelly said Dunbar's concern was obvious.

"He described her as a very hurt and very frightened human being, and he questioned why the authorities hadn't looked for her earlier," she said.

A few days later, Dunbar rang the social worker to tell her that he had made phone contact with Melissa and he would try and get her to contact social services. He quickly became the HSE's link with the missing teenager and they were grateful for his help.

Since Melissa was alleging sexual and physical abuse by her parents and was regularly disappearing for long periods, the decision was made to take her into residential care. She didn't like the idea. It was Dunbar who eventually convinced her to go into the residential care home, Lios Na nÓg, in August 2006. She had wanted to go live with Dunbar but he was less than keen.

But Melissa didn't settle in her new surroundings: out of the 16 nights she spent there, she was missing without permission for half of the time and was regularly found in the Dunbars' house.

"We were concerned with the level of contact she was having with the Dunbars," Donna McTague, social worker at the care centre, told the court.

Eventually, a week before her final disappearance, the HSE went to Sligo district court and obtained a court order prohibiting contact between Melissa and Ronnie Dunbar. She was never going to settle into her new surroundings unless she broke her ties with the Dunbar family, the HSE believed.

But the attempt to cut her off from the family she relied on so heavily made her behaviour deteriorate further. After she was picked up by gardaí in the Caltra housing estate area of Sligo with another girl from the care home, having superficially cut her arms with a piece of glass they found on her person, it was decided she would be better off in temporary foster care.

At first Melissa appeared to settle in well in the foster family's home in Kinlough, Sligo, but she ran away in her bare feet after a few hours, having received a phone call that seemed to agitate her. She ran to a nearby house and asked them to telephone Dunbar, who she said was her father.

"She gave us his number and said she had fallen asleep under a tree and didn't know how she got there," according to Hugh Fergus's statement.

Dunbar denied she was his daughter when contacted that night and called the gardaí and social services. Melissa was taken back into care and the next day seemed to calm down. After being taken to Markievicz House Health Centre in Sligo, she agreed to try another foster family. But when the social worker left the room to contact the foster family, Melissa disappeared. She was later seen making her way towards the Rathbraughan Estate, where Dunbar lives. That was the last time anyone from the HSE saw her.

While social services were initially grateful to Dunbar for helping them with Melissa, they soon felt her reliance on him and his family was unhealthy. His ex-girlfriend also had concerns about the 44-year-old's relationship with the teenager. Sheridan, who dated Dunbar in the weeks before Melissa went missing, said one of his daughters told her Dunbar and Melissa were in a relationship. She said she was also told "Melissa was pregnant with Ronnie".

Brendan Grehan, defending Dunbar, told the court it was alleged Melissa was three months' pregnant. Because 15 months passed before her remains were discovered, it will never be known whether the teenager was pregnant or not.

Overheard conversation

Sheridan also said she overheard a conversation in her flat between Dunbar and his eldest daughter Shirley, in which a plan to kill Melissa was discussed. Sheridan said that, during the conversation, Dunbar said he wasn't "going to prison" for Melissa.

"Shirley said something about going to prison. He said he wouldn't go to prison for her, he'd kill her." He intended to strangle Melissa, she calmly told a shocked courtroom. "He said he would kill her, strangle her. He had it planned… He said, 'Isn't that right Shirley?' He had it planned."

When she questioned Dunbar about conversation with his daughter, she said he was very calm and said they were "just teenagers".

Sheridan did not go to gardaí with these "explosive" claims until April 2008, after Dunbar had been arrested and charged with Melissa's murder. She initially contacted gardaí in September 2006 with her concerns but did not mention the alleged plan to kill Melissa. She was frightened of the accused, came her reply, after a moment's consideration. Not so, insisted Grehan, who said the murder plans were "a total figment of your imagination".

Shirley, who is due to testify during the trial, has no recollection whatsoever of this conversation, Grehan added.

Sheridan told the court Melissa was a troubled young girl. "Melissa told me she was Cleopatra incarnated and Ronnie was reincarnated as a lord or husband and they were going to move to the highlands to a new world," she said.

Melissa's sister Leanna (19) was also a frequent visitor to the Dunbars' home. She recalled one occasion when she saw the accused lying on the sofa with Melissa sitting between his legs with her head on his chest. After Melissa went missing she found a photo of the accused in a box in Melissa's bedroom. She said her sister was very close to Dunbar and he once asked her to rub Vaseline into one of his tattoos on his arm.

The accused's daughter Samantha, Melissa's closest friend, is due to give evidence by video link stating that she saw him lying in bed with Melissa with his arm across her neck.

The jury has been told the teenager will give evidence that she saw her father put Melissa's body in a sleeping bag that was tied at the top with a man's neck tie before loading it into his blue Fiat Cinquecento. He then dumped the body in the River Bonnet before bringing Samantha and her sister Heidi to football, it is alleged.

Allegations of abuse

Melissa's mother Mary gave evidence in a distanced and distracted manner. She told the court she moved back to her home county of Sligo from London, where she had emigrated with her husband Freddie, in July 2005.

The family moved to Garavogue Villas, Sligo, before moving to Rathbraughan Park in the town, where Dunbar also lived with his family. Her two daughters, Melissa and Leanna, became very friendly with Samantha and Heidi Dunbar. They visited their home almost every day, and the accused took them out in his car.

Under cross-examination, she agreed her family had been engaged with social services in England and two older daughters were on the child-protection register there.

She said she was aware Melissa had alleged she had been abused physically by her mother and sexually by her father but refused to discuss it any further.

Questioned about why she declined to make a statement to gardaí when her daughter went missing, she gave the impression it was none of her concern: "It wasn't up to me; she wasn't in my care."

The trial continues.