A pensioner went on a vicious "stabbing spree" outside a supermarket, injuring four innocent women, a court has been told.
They were picked at random by Ethem Orhon, who wanted to "get revenge on police for what he perceived as their mistreatment of him", prosecutor Jonathan Polnay told Kingston Crown Court.
Orhon, 67, of Deacons Walk, Hampton, west London, has pleaded not guilty to two counts of attempted murder and two of wounding with intent to cause grievous bodily harm.
The women - Suzanna Brand, 53, Janet Morsey, 63, Jean Sullivan, 68, and Charandasi Chandiramani, 71 - suffered "serious and appalling injuries" in or near the Sainsbury's car park in Hampton, west London, on May 20.
The "true bravery" of two schoolboys - who distracted Orhon, warned others that he was armed and dangerous, called police and stayed on the telephone with the 999 operator during the rampage - potentially stopped further bloodshed, the jury was told.
Speaking of the boys, who cannot be named for legal reasons, Mr Polnay said: "Without their help it may be that more people would have been injured by this man."
Holding up a knife with a 4in blade, Mr Polnay told the jury that Orhon "plunged this knife at least 20 times into four innocent members of the public who had been doing their shopping".
Orhon had been picked up the day before by police outside a public toilet in Kensington, central London, the court heard.
They had suspected he might have drugs but Orhon was found with a Leatherman knife, the jury was told. He was charged with having a bladed article and released on bail.
Orhon went back home, just 10 minutes from the Sainsbury's, and picked up his spare Leatherman knife and went straight back out, the court heard.
He was wearing the same clothes from the day before and carrying a rucksack containing Turkish identification materials, a UK passport, 1,075 euros and £307.87 in cash, the jury was told.
The court heard Orhon later said in a police interview that he had felt "mentally tortured" by police, adding: "I went home and got my other Leatherman. I shouldn't have done it. I feel bad. It was a loss of control. I felt humiliated."
Miss Brand, who has learning difficulties, was on her way to meet her mother when she was attacked from behind.
Mr Polnay said: "He stabbed her 13 times to the back, side and arms. She collapsed and all she was able to do was to kick out when she was on the ground. She suffered very serious injuries, as you would expect. Her back was covered."
She suffered two collapsed lungs and a laceration to her liver.
Horrified onlookers, including the schoolchildren, other shoppers and passers-by, saw the attack.
One of the schoolboys said Miss Brand was in hysterics, screaming her head off and saying "Did he stab me?"
Ms Sullivan had just finished her weekly supermarket shop when she turned round and saw a man behind her.
She was unable to defend herself because she had her hands full with shopping and she felt the man touch her and run off.
As she got into her car and locked the doors, she heard a woman shouting "Don't stab me" - it is likely this was Ms Morsey, the jury was told.
Ms Sullivan saw the man who had hit her walk off "as if nothing had happened", Mr Polnay noted.
It was then that she realised she had been stabbed in the back. Her chest wall muscle, her right lung and her liver were damaged.
Miss Chandiramani was waiting at a business stop when she heard a woman screaming.
She made eye contact with Orhon, who then "ran towards her at speed", Mr Polnay said.
Despite "running for her life", she felt two hits to her lower back, the court heard.
Ms Morsey, speaking from behind a screen, told the jury that she had just left her car while on the way to work when she heard a woman shouting "there's a man with a knife".
She told the court how a dirty, swarthy-looking man, about 6ft 3in, with a beard towered over her and "did not say a word or make a sound".
Ms Morsey, who is 5ft 3in and could not run because she has balance problems, also spotted a dirty blade in his hand.
She said: "I looked him in the eye and he looked me in the eye and I said 'please don't hurt me'.
"He started to lurch towards me. He was looking down on me and I was paralysed to the spot."
He took a "strong" swing and she felt a "thump" to the right side of her chest behind the rib cage.
She was "terrified" he was going to hit her in the face and she continued to scream as he stabbed her in the arm as she tried to protect her upper body.
Ms Morsey said: "I thought I was going to die in Sainsbury's car park ... Then suddenly he had gone.
"I was standing there stunned, seeing stars and trying to stay conscious and calm. I could feel the sharp prickling in my chest."
She managed to call work to say she would not be in before being rushed to hospital.