The number of killings in London has reached the highest number for a decade.
The fatal stabbing of 18-year-old Jay Sewell in Eltham on Tuesday night means there have been 130 homicides in the capital since 1 January.
The figure, which includes murders and manslaughters, is the highest number since 2008 when there were 154 deaths in a year.
A spokesperson for London’s mayor described the increase as “shameful”.
The Met Police said it was “committed to reducing violent crime.”
The 130 homicides this year has included 73 stabbings and 14 shootings.
Mr Sewell, from Kent, died in a south London hospital after he arrived with another 18-year-old. Both of them had suffered serious stab wounds.
They had been injured at about 21:50 GMT in Alwold Crescent where there were reports of armed youths in the street.
Scotland Yard said five people – two women aged 53 and 29 and three men aged 56, 31 and 22 – had been arrested on suspicion of murder and all were in custody.
The other man who was treated in hospital has since been discharged.
Another teenager was stabbed to death in the same borough on Saturday, while the death of a 77-year-old woman who collapsed while calling police about a burglary is being treated as manslaughter.
Earlier this year it was announced the city would follow Scotland’s public health approach to help tackle violent crime.
A spokesperson for the mayor said the approach was helping to tackle “the root causes of violence”.
“The causes of violent crime are deeply complex and made far worse by huge government cuts over the last eight years to the police, youth services, councils and charities,” the spokesperson said.
Scotland Yard said its officers continued “to be relentless in our pursuit of those who choose to be violent” although “policing alone” would “not solve the problem.”
“We are committed to a longer-term sustainable solution working with all agencies that are prominent in communities… and with local people themselves,” a spokesperson said.