The family of 12-year-old refugee Shukri Abdi who drowned in June have branded an internal investigation into claims of bullying before her death “a whitewash”.

Shukri was found drowned in the River Irwell in the Lancashire town of Bury on 28 June. She came to the UK from Somalia last year with her mother and siblings after fleeing conflict.

Members of Shukri’s family claim she was badly bullied at the school, Broad Oak sports college in Bury, for more than a year but that the school failed to respond to her family’s concerns. They accuse the school of failing to take the bullying complaints seriously.

The school agreed to conduct an internal investigation into the claims and on Friday afternoon called the family to Bury police station to provide them with the conclusions.

Shukri’s uncle Mustaf Omar, 29, said: “We are not happy with the lack of information in the report. It’s a whitewash. We hoped the school would interview Shukri’s mother for this report and other parents whose children might have experienced bullying but they weren’t approached.

“It was very insulting that we were asked to go to the police station to receive this school report. We asked for an interpreter for Shukri’s mum, Zamzam, but there was no interpreter there. Zamzam just sat there crying. In the end we walked out of the police station in protest about the way we were treated.”

The family’s lawyer, Attiq Malik, of Liberty Law Solicitors said: “The family are very unhappy with this report. Despite assurances from the school that a full review would be carried out this has not been done. The family have lost trust in the police and now they have lost trust in the school too. The family is turning to the community for help. We hope other members of the community who have evidence relating to this case will now come forward.”

Shukri’s mother, Zamzam Arab Ture, is calling on the school to be investigated for a potential breach of its duty of care towards pupils.

She said: “If the rights we came to this country for exist I want something done.”

Friday’s report was the result of a review of the school’s anti-bullying policy announced by the headteacher of Broad Oak sport college, Paul Greenhalgh, in the wake of Shukri’s death.

The Guardian has seen an account from another student at the school who is thought to have been a victim of the same kind of bullying Shukri was subjected to. The girl said her problems had gone on for more than a year, that she had been grabbed and seriously assaulted by another pupil and struggled to cope. She said that although she had reported the bullying to the school nothing had been done and she felt unsupported.

The girl’s mother raised concerns about bullying at the school with both the school and police but said that neither had responded appropriately. The mother added that some pupils who were victims of bullying were too scared of reprisals from the bullies to speak out about their experiences.

Saynab Hareed, Shukri’s aunt, described the difficulties Shukri had had fitting in and said that teachers would sometimes bring her home themselves from school amid fears for her safety. “She had been telling us of the bullying for months,” said Hareed. She added that things became so bad at one point that a teacher decided to remove her from school in a desperate attempt to protect her.

Shukri’s family said she helped look after her four younger siblings, supported her mother and dreamed of becoming a doctor.

An investigation has been launched into whether police treated Shukri’s family “less favourably” because of their ethnic background.

On Thursday, the Independent Office for Police Conduct (IOPC) announced it had begun an investigation after a complaint about police actions following Shukri’s death.

An IOPC spokeswoman said: “In July the force referred a complaint they had received about their actions; it alleged that officers failed to conduct an effective investigation and prematurely concluded that the death of Shukri Abdi was not suspicious.”

A separate investigation into her death by Greater Manchester police was continuing.

A GMP spokeswoman said: “We will liaise with the IOPC to ensure that they are provided with any information they need. It would be inappropriate for us to comment any further at this time.”

A public meeting has been organised for Saturday by the Justice4Shukri Campaign. Campaigners are calling for an investigation into the numerous complaints of bullying at the school, actions to prevent further tragedies from happening and transparency around the investigation into Shukri’s death.

Caroline Bailey, a teacher at Broad Oaks School, took her own life in September 2012 following claims of bullying there.

The school has been approached for comment.