A 22-year-old man chased by a group and knifed to death in one of a spate of stabbings in London over the weekend has been named by police. The Metropolitan police have enacted additional stop-and-search powers and beefed up patrols after the series of incidents in the capital, believed to be unconnected, which left two young men dead, a 16-year-old critically ill in hospital and 11 others wounded. One of the two fatalities was named on Sunday as Sven Badzak, who died in hospital after being stabbed while walking with a 16-year-old friend in Kilburn, north-west London, at about 5.30pm on Saturday. His mother, Jasna Badzak, a former Conservative activist, shared pictures on Twitter of her son, as a child, with Boris Johnson, David Cameron and George Osborne, and appealed to the prime minister, former prime minister and former chancellor to intervene in the case. She told the MyLondon website her son had gone out to the shops to pick up some orange juice and was the “nicest of nice kids”, adding: “He was the most polite boy you could possibly imagine. The perfect manners … He was beloved by everybody.” Ch Insp Darren Jones of Scotland Yard said: “At this early stage we believe Sven and his friend became involved in an altercation with a group of males. As this group chased the pair, Sven and his friend became separated. Sven fell to the ground and was attacked by a number of the group. “His friend was also attacked but managed to seek sanctuary in a shop – however, he remains critically ill in hospital.” The weekend’s violence began on Friday evening, when five stabbings were reported in just over three hours in south London, leaving one man dead and nine people injured. No arrests have been made after a 22-year-old man died in an altercation with a group of males at a property in Croydon. One neighbour told PA Media she saw police and medical staff trying to save a heavily bleeding young man. The victim’s mother showed up “crying and in pieces”, the witness said. Elsewhere in Croydon, two people were arrested after a man in his 40s was found with a stab wound at an address on Dingwall Road. The victim was later arrested on suspicion of affray and a 38-year-old man was arrested on suspicion of grievous bodily harm. Police said none of the nine other casualties from the five incidents was considered to be in a life-threatening condition. At about 11.20am on Saturday officers were called to reports of a fight in Coulsdon, south London, where a man in his 20s had been stabbed and was taken to hospital. Two men have been arrested. Then shortly after 3pm police were called to a stabbing of a 24-year-old near West Croydon station. Scotland Yard said more officers had been deployed in response to the violence. Sarah Jones, the MP for Croydon Central and Labour’s shadow policing minister, said it was an “incredibly unusual and sad situation with so many incidents in 24 hours, but they are all unconnected and people can rest assured the police are doing what is required”.