The mother of Ana Kriegel has described how her daughter was left terrified by people who "endlessly bullied" her.
Geraldine Kriegel told a court that her 14-year-old daughter, whose naked body was found in a derelict house in Lucan, Co Dublin, days after she went missing last year, struggled to make friends and was targeted by bullies.
Two 14-year-old boys have pleaded not guilty to the schoolgirl's murder. Boy A also pleaded not guilty to aggravated sexual assault.
The boys cannot be identified because of their age.
On the first day of the trial at Central Criminal Court, Mrs Kriegel said Ana was adopted from Russia when she was two and a half years old.
She said Ana had a tumour in her right ear which had affected her hearing "very badly". In 2010 she underwent a five-hour operation to remove the tumour.
"She could hardly hear in her right ear and she had poor eyesight," her mother said.
Ana was a member of a local dance group, which she loved.
"Dancing was her passion, she loved it," Mrs Kriegel said. "She spent hours in the front room practising her dancing, listening to music and singing. She sang and did gymnastics and she was a great swimmer."
"She was incredibly excited to start (secondary school). We were hoping she would make friends in the community."
She told the court that Ana's primary school teacher rang her and her husband Patrick to express concerns about Ana going to college.
"The resource teacher said she was was terrified for Ana going to college because she was so vulnerable and innocent in her manner that children might make a mockery out of her.
"She was so concerned people might take advantage of her. She said we should ring the principal and we did. We expressed our concerns about her vulnerability. She didn't mix well and was a bit of a loner."
Her mother also told the court that Ana was cyber-bullied by a number of older students.
"(They) sent awful messages," she added.
Mrs Kriegel took screenshots of some sexually explicit messages sent to Ana and brought them to the attention of the school principal.
Ana received other "rude messages" about her height and how she had a "fake mum and dad".
"There were awful, insulting things to make her feel small," Mrs Kriegel added.
She told the court that Ana created a YouTube account and uploaded videos of her dancing, but these also attracted nasty comments.
"One said he would have her executed," she added. "Another said 'go die'."
She also described an incident in which Ana was attacked by four boys in October 2017, when she was 13, after one of them asked her to have sex with him.
"He hit her on the bum and she panicked and ran home. She was hysterical, she was really frightened. I held her for an hour," she said.
Mrs Kriegel said Ana was not academic as she struggled with her hearing and eyesight, but she volunteered in many areas, helped younger students and took part in a modelling fundraiser.
Ana's mother will continue her evidence on Wednesday.
The court also heard evidence from Mrs Kriegel's son, who was one of the last people to see Ana alive.
Witness one told the court that he answered the door to Boy B on the day she went missing in May last year.
The then 12-year-old said he went to her bedroom to tell her that Boy B had called for her.
Asked what her reaction was, he said: "She was kind of confused. She just said, 'Are you sure it's for me?'"
Ana spoke to Boy B at the front door for around five minutes, the court heard. She then left the house saying she was going out and would not be long.
The court heard that after Mrs Kriegel returned home and found that Ana was out with Boy B, she texted and rang her daughter a number of times but could not reach her.
The family searched the area for a number of hours before contacting gardai to report her missing.