The mother of an 11-year-old girl who was chased through a park by a child apparently holding a knife said her daughter had been left devastated by the ordeal.
Janine Sikes, 42, from Thurmaston, said she was furious when she found out her daughter, Amber, had been the focus of the unprovoked attack.
Amber was at Willowbrook Park, in Thurnby Lodge, Leicester, with her 11-year-old friend after school on Thursday when a boy produced a retractable craft knife and ran at the pair, shouting, "I'm going to kill you".
The girls ran home and called the police.
Officers arrested and bailed a boy, believed to be aged 11, later that day and found the plastic handle of a craft knife like the one described by the victims, but did not find a blade.
Amber, who goes to Hamilton Community College, in Keyham Lane, Leicester, said: "We were at the park and he started to throw bark at me.
"He chased us and got his knife out. He said he wanted to kill me. We were scared. I'm still scared to go outside."
Janine said: "She was devastated and her friend had an asthma attack."
Janine said after police had told her they could not find the blade, she went to the scene with Amber and found a discarded craft knife blade, which she took to Hamilton police station.
A police spokesman confirmed officers had arrested a person. The suspect has been released on police bail.
Anyone with information can call police on 101.