Speaking in the House of Lords on Wednesday, Baroness Lawrence, the mother of the murdered teenager Stephen Lawrence, shared her condolences with the Nowak family.
She said: “I think what’s happened with him should never have happened.
“And the police should be at fault for what happened on that night.”
Earlier this week, Reform UK leader Nigel Farage said the public should react to Nowak’s death with “pure, cold rage”, leading Sir Keir Starmer to accuse him of exploiting the case to create “grievance and division”.
Protests following the sentencing of Nowak’s killer led to violent clashes between police and protesters on Tuesday near the site of Nowak’s stabbing.
Eleven police officers were injured and two people have been charged with criminal offences.
After the sentencing of his son’s killer, Nowak’s father Mark said it was “unbearable” to see how his son had been treated by police in his final moments, but added: “We do not want his death to be used to create further division, hatred or tension.”
Alexis Boon, chief constable of Hampshire Police, apologised to Nowak’s family on Wednesday.