The mother of a nine-year-old boy who was found hanged in his bedroom has claimed at an inquest that he was bullied at his primary school.

Kelly Dugmore told the inquest in Birmingham that her son, Aaron, had not been happy at school and said it had even crossed her mind that a fellow pupil might have suggested he harm himself.

Shortly after his death in February last year, his family was quoted as claiming Aaron, who is white, was bullied because of his skin colour. This led to a neo-Nazi protest outside the school.

Birmingham safeguarding children board is conducting a serious case review into Aaron's death.

Jane Held, the board's independent chairwoman, said: "This was a tragedy for Aaron and his family. The board has nearly completed a serious case review.

"After completion, we will share the report with Aaron's family and will consider how best to use the findings to help other children and families so they don't have to face a similar tragedy."

DI Richard Scott, of West Midlands police, said that officers investigated the family's complaints that Aaron had been bullied at school. He told the inquest that while there had been some incidents involving "different individuals", officers had found no evidence of systematic bullying.

Dugmore told the inquest that on the day of the tragedy she picked Aaron up from Erdington Hall primary school. She said he told her there had been an argument with other pupils. "He wasn't happy," she said. "He wasn't happy since being at that school."

At home he asked to play outside but his mother told him he could not as it was snowy. He argued with one of his siblings and was told to go to his room to calm down. Dugmore said she later told one of Aaron's brothers to go and tell him dinner was ready.

She said: "I heard him [the brother] screaming, 'What have you done?'" She went up and found Aaron hanging. "I got him down.

"I was just screaming … screaming his name." She tried to give him mouth-to-mouth resuscitation.

Aaron was taken to Birmingham children's hospital in cardiac arrest. He was stabilised and taken into intensive care but suffered another cardiac arrest and died the next day. A postmortem concluded he died of severe brain injuries.

Dugmore said that Aaron had never given her cause for concern that he could take his own life. But she said that since his death it had "crossed my mind" that one of the children at school could have told him, "Go and do something". She added: "I don't know that for sure."

The coroner, Louise Hunt, concluded that Aaron's death was an accident. She said she could not be sure that he had intended to take his own life, giving his age as one reason why a conclusion of suicide was not appropriate. She described his death as an "absolute tragedy".

Hunt said: "The evidence available to me confirms that Aaron was having what appeared to be a perfectly normal day – he went to school and came home as normal. There was an altercation in the house and he went to his bedroom.

"It's clear that mum and stepdad did everything they possibly could to administer first aid – full credit to you for everything you tried to do."

No one from Aaron's school was available for comment.