Police referred themselves to the watchdog over the murder of Yasmin Chkaifi who was stabbed by her ex-partner. She had a restraining order against him. Tap above to watch video report by Sam Holder
Thousands of people have signed a petition branding a driver who ran down a knife attacker "a hero" and calling for him not to face criminal charges.
The 26-year-old was arrested on suspicion of murder after driving into into Leon McCaskre, 41, as he stabbed his former partner Yasmin Chkaifi to death in the street in Maida Vale in front of horrified witnesses.
A number of people had tried to stop McCaskre before the driver hit him with his car in Maida Vale, west London on Monday morning.
Relatives of Yasmin Chkaifi, who had two sons, have reportedly also praised the driver for attempting to stop the fatal attack.
He was arrested on suspicion of murder and has since been released on bail until late February while the police investigation continues.
On Wednesday nearly 5,000 people had signed a petition on Change.org entitled: "Maida Vale driver is a hero and shouldn't be charged with murder".
One of Yasmin's friends said she lived in fear that her former partner would kill her.
Adele-Sara Richards said in April 2020 Ms Chkaifi messaged her to say: "He’s had cameras in my house recording me for months."
She went on: “He’s stolen my mail, my phone, has access to all my personal data.
"I think he will kill me. I’ve tried everything."
One of her sons told MailOnline that she had been continually harassed by her ex-husband, who had made her life “hell”.
He said: "It was a very abusive relationship which got worse after the divorce.
"My mother was continually being harassed and intimidated by this man.
"He made her life hell.
"I was always in touch with the police but they did nothing to help her.
"There was even a panic alarm installed in our flat – that’s how scared she was of this man.
"He was a monster."
Tributes have also been paid to Ms Chkaifi, who was a qualified childminder, had worked in a school and was studying for a master’s degree.
American PhD student Olivia Jones, 30, who lives in Brent, said: "I didn’t know Yasmin well, but she made me feel as though I did. A year ago, Yasmin opened her doors to my partner and I at the time and hosted us for a meal.
"She was incredibly kind, hospitable and an amazing cook and dancer. She had a bubbly personality and a confidence about her that was so attractive.
"She was proud of her Moroccan heritage and a spiritual woman. We spoke about Islam, identity and social justice. She was a good person."
Family members also paid tribute to Yasmin Chkaifi, who was also known as Wafat, in a statement on Facebook.
They said: "She was full of life, always stayed positive and always saw the best in everyone.
"Wafat loved to laugh, dance and leave a special impact on everyone’s life that got to share it with her. She has indeed left many broken from this awful and tragic news.
"Wafat was the most pure and genuine soul you would meet. She has left two amazing boys who will continue her legacy of being pure souls."
Detective Chief Inspector Neil Rawlinson, of the Met’s Specialist Crime Command, said members of the public had "bravely tried to intervene to stop the attack and their actions were very courageous".
He said the force was "gaining a clearer idea of what happened at the scene thanks to information supplied by the public and by reviewing CCTV".
He added: "We are speaking to the families of those concerned and doing all we can to support them at this terrible time.
"A man, who was the driver of a car, has been arrested and bailed for a very serious offence and we must carry out a full investigation, looking at all the circumstances."