A woman who struck a 12-year-old black boy on the forehead with a paddle at a riverside park so forcefully that he has been left scarred has admitted assault causing actual bodily harm but insisted the attack was not racially motivated. The police were strongly criticised after the attack by Fay Johnson, 32, on the boy, because she was initially not prosecuted after claiming she acted in self-defence and felt “threatened” by the youngster. It was only when campaigners and relatives of the 12-year-old posted images of his bleeding head on social media and questioned why Johnson clashed with him rather than his white friends that Avon and Somerset police began a review, reclassified the incident as racially motivated and apologised. Johnson, from Yate in south Gloucestershire, who at the time worked for a luxury car dealership, looked tearful in the dock at Bristol magistrates court as she admitted the assault. She will be sentenced at Bristol crown court next month and could be jailed. The incident took place at a riverside park on the outskirts of Bristol on 26 March when the boy met a group of friends for a birthday party. Some children are said to have thrown mudballs at passing boats, including one being paddled by Johnson. She struck the boy on the forehead with her paddle, leaving him bleeding from a 1cm wound that needed gluing in hospital. Steve George, defending, successfully applied to the court to ban Johnson’s full address from being published because she has received death threats. He said: “The defendant is in fear that if her address is published she and her young children would be subject to risk of death or serious injury.” The court was told that in the aftermath of the attack, Johnson was accused on social media of being a racist and threatened. George told the court that those who had threatened her were working on the “mistaken impression that this was racially motivated”. He said his client’s “significant fear” was for her children and revealed that one of them had had to move school because of the threats. Outside court, members of the victim’s family told the Guardian he remained traumatised. “Every time he looks in the mirror he sees the scar and is reminded of what happened,” one said. “He’s a quiet child who wouldn’t harm anyone and wants all this over with.” The family expressed concern that Johnson had faced threats and sorrow for what her children were going through. But they criticised the police’s handling of the case. “What they did was terrible. They even gave her [Johnson] a lift home.” The prosecution did not open the facts of the case before the district judge Lynne Matthews on Thursday. The boy’s family has previously described how, three weeks after the attack, a letter arrived from the police telling them no further action would be taken. It explained: “The main reason is that during interview the suspect raised a possibility for self-defence. The suspect claimed … she felt threatened by [the boy] and the surrounding group.” After the outcry, the police looked again and said: “We’ve reclassified this incident as being racially motivated and we have a detective sergeant leading [the] review, with oversight from a senior officer.” Ahead of Johnson’s court appearance, neighbourhood Ch Insp Mike Buck said: “We listened to the concerns of the family and the community … and carried out further investigation.” Johnson was given bail and will be sentenced on 12 January.