A bystander who witnessed a man violently stabbing a woman outside a school got into his car and mowed down the killer.
Wafah Chkaifi, 43, was fatally stabbed by her ex-boyfriend Leon McCaskre, 41, moments after she dropped off her two children at school on Monday morning.
The horrific incident happened at 9 a.m. at a school in Maida Vale, West London.
Another parent who witnessed the stabbing got into his car and mowed down McCaskre near the school.
Police arrested the driver, a 26-year-old man, on suspicion of murder but he has since posted bond.
Heartbroken family members called the driver a "hero" for attempting to intervene and save Chkaifi, who filed for a restraining order after years of abuse.
"The man who killed my sister is a demon. The man who killed him is a hero. He deserves a medal from the queen," a family member told The Sun UK newspaper.
"There is no way he should go through the justice system for what he did. He tried to help her and for my sister and our family he is a hero."
The family member said McCaskre had a court date for violating a restraining order against him.
"He was supposed to be in court last week for breaching a stalking order but didn't show up. My sister even has a panic alarm in her flat to protect herself from him. The police are aware of his past but this still happened. He was a demon. He was a monster but the driver is a hero. He saw what was happening and tried to stop it. I want to say thank you again."
Her son added: "Everyone who knew my mum knows she was a good woman. She didn't deserve this. Keep her in your prayers."