Ayaan Ali, 29, stabbed shopper Andrew Froggatt in the town centre on Saturday September 8 last year and also tried to attack another man - a window cleaner - who fought her off with his bucket.
Ali, of Isleworth, West London, bought a pack of knives from a discount store ‘minutes’ after arriving at Barnsley Interchange.
Appearing via video link at Sheffield Crown Court, Ali was found guilty of attempted murder, possession of an offensive weapon and affray this week.
Judge Peter Nelson QC ordered an indefinite hospital order due to Ali’s mental state after the court was told she is a paranoid schizophrenic. She had previously pleaded not guilty to the charges by virtue of insanity.
Kate Batty, prosecuting, said the question was whether Ali knew what she was doing and told the court she had stabbed Mr Froggatt after chasing him for about 100 metres through the town centre.
In a video interview played to the court, he said: “She was brandishing the knife and going ‘kill, kill, kill’. That’s all she said - ‘kill, kill, kill’.”
In the hours after the incident, rumours circulated on social media about the nature of the attack, the number of people involved and their nationality.
Some people even posted a link to what they believed to be the culprit’s Facebook profile.
Dpt Chf Con Mark Roberts said such comments were not uncommon, and can cause distress and fear.
He said: “The comments were vile and offensive and ironically, the bigotry expressed re-emphasises the need to tackle hate both within our local communities, and much wider.
“Unfortunately, we see this type of offensive content on a regular basis. This will undoubtedly cause distress and fear to people within our communities. We have seen unacceptable comments, and will seek to prosecute those responsible where appropriate.
“We will not tolerate this type of messaging and will continue, together with our partners, to raise awareness of hate.”
South Yorkshire Police ‘definitively confirmed’ the act was not one of terrorism the following day.
Eyewitnesses said the incident was frightening for a short while confirming they had seen a woman with what looked like a kitchen knife, but the trouble was over quickly and traders were soon back to ‘business as usual’.
Abdul Razzaq, of nearby stall Fashion and Style, followed Ali around to try and make sure nobody else got hurt.
“I didn’t feel frightened,” he added. “I just care about people and wanted to make sure everyone was OK.”
A spokesman from South Yorkshire Police added: “Members of the public, while going about their normal business on a quiet Saturday morning were suddenly beset by Ali, who was in possession of knives. She was quickly arrested and it is fortunate that no-one else was injured.
“This verdict and sentence prevents her from being a future risk to the public.”