The girlfriend of Alesha MacPhail’s father has denied any involvement in the six-year-old’s death.

Toni McLachlan has been named by the accused, who cannot be identified, for legal reasons, and who denies abducting, raping and murdering the child last July on the Isle of Bute, in a special defence as the person responsible for the killing.

McLachlan told the high court in Glasgow that she did not have anything to do with the murder and that she had loved the child to bits.

Alesha, from Airdrie in Lanarkshire, was found dead in the grounds of a disused hotel near her grandparents’ seafront home, close to the ferry port of Rothesay, where she had arrived a few days previously to spend a three-week summer break.

McLachlan told the prosecutor, Iain McSporran QC, that she had become aware that the 16-year-old accused was saying that she murdered Alesha on Monday, when the trial began.

Asked by McSporran how she felt about the accusations, which were put to her on the third morning of the trial, including the allegation that she smeared the contents of a used condom on to Alesha’s body to incriminate the accused, she replied: “Horrible”.

“But she knew that I loved her and that’s what I’m trying to keep in my head. I’m sad, I’m hurt, I’m angry, lots of different emotions,” she said.

Pressed on the “appalling” nature of the injuries inflicted on Alesha, McLachlan broke down and again insisted that she had nothing to do with the killing.

The court heard on Tuesday that Alesha’s grandmother, Angela King, had noticed she was missing early in the morning of 2 July last year, and posted an appeal for help on Facebook, prompting a frantic search by locals on the island. A member of the public found Alesha’s body approximately half a mile away at about 9am.

Under lengthy cross-examination, McLachlan, 18, repeatedly answered “no” as Brian McConnachie QC for the defence laid out a scenario that involved her previously having a sexual relationship with the accused, and having sexual intercourse with him again on the night of Alesha’s disappearance.

She further denied that she had kept the condom from that liaison and used it to plant evidence on Alesha, having taken the child from the flat herself to nearby woodland, where she murdered her.

Alesha’s father, Robert MacPhail, admitted on Tuesday that he had regularly sold cannabis to the accused, explaining that the defendant would message him via Facebook and the drugs would usually be handed over at the bus shelter opposite his parents’ flat.

McLachlan told the court on Wednesday that she was not seriously worried by the girl’s disappearance at first: “I just couldn’t believe it, but I didn’t think anything bad because I know Rothesay is a safe place. I’ve stayed there all my life.”

She said the accused had tried to contact her overnight when the girl disappeared. “As soon as I got up I noticed missed calls … on Facebook Messenger. I tried to phone back [at 6.29am] just to see what he wanted. I thought it was a bit strange at first.”

McLachlan said the accused had sent her another message later the same morning. “He messaged me again I’m assuming when he woke up saying that he didn’t mean to phone.” She had explained to him that Alesha had gone missing and asked him to keep an eye out for her, she said. The court heard that he replied: “Oh damn. Hopefully she’s not went too far”.

Asked if it would surprise her that people felt she was jealous of Alesha and threatened by the time and attention that Robert gave to her, McLachlan responded: “I always knew that Alesha would come first. I knew that if I wanted to be in a relationship with Rab I would need to accept them both.”

Questioned about evidence from Angela King’s neighbour that she had heard McLachlan shouting for help and the sounds of violent arguments when the couple were staying together in the grandparents’ flat, she denied that too.

The court later heard that the police had initially interviewed the accused as a witness, after his mother informed them that he had left the family home in the early hours of the day that Alesha disappeared.

Describing the teenager’s behaviour as “very cooperative”, detective constable Gavin McKellar told McSporran that the accused had provided a detailed account of his movements during the night and early morning as he walked around the local area trying to buy cannabis, but did not mention any interaction with Toni McLachlan.

The trial continues.