A 15-year-old boy who was stabbed to death in south London has been named by police.
The Metropolitan Police said a post-mortem examination gave the cause of death as a stab wound to the heart.
A 15-year-old boy remains in custody on suspicion of murder.
Less than an hour after the attack, a 16-year-old boy was fatally wounded at Philpot’s Farm, in Yiewsley, west London, and was pronounced dead at 8.25pm.
The number of teen homicides in 2021 has now surpassed the peak of 29 in 2008.
Scotland Yard said there was no intelligence to link the two incidents, which happened more than 20 miles apart, but called on parents to talk with their children about the impact of carrying weapons.
Detective Chief Inspector Richard Leonard, who is leading the Specialist Crime Command investigation team, said: “My thoughts continue to be with Zaian’s family and friends as they cope with this tragic loss.
“My team are continuing to work around the clock so that we can give Zaian’s family the answers they deserve.
“Zaian’s death has sent shockwaves through the local community and London as a whole.
“He was just 15 years old and had his whole life ahead of him and we need the community to work with us to bring those responsible to justice.
“No matter how insignificant you may think it, if you have information that can help, you must do the right thing and contact us immediately.”
Detective Chief Inspector Jim Shirley, who is leading the Yiewsley investigation, added: “I am urging anyone with information, or who saw the attack, to come forward and speak with us.
“We need to establish what happened and find the person who is responsible.”
The double tragedy brings the total number of teenage killings in the capital in a calendar year to 30 – passing a previous peak of 29, set in 2008.
The seriousness of the situation was further underlined by Pastor Beryl St James, from Shiloh Worship church and charity in nearby Thornton Heath, who told the PA news agency she had just received a call from a parent who had found a knife in their child’s room that morning.
Also speaking from the scene, she added: “I know we have to work and we all have duties to fulfil, but as a parent you cannot think that’s it OK to leave the state to continually look after your child.”
Patrick Green, chief executive of anti-knife crime charity the Ben Kinsella Trust which was set up in 2008 following the fatal stabbing of 16-year-old Ben in north London, echoed Mr Murray’s comments.
He said: “Knife crime is accepted by this generation as part-and-parcel of growing up and that’s completely unacceptable.
“It shows that not enough has been done and if I’m being really critical then I’d say the approach to tackling it has been scattergun.
“We have to sustain our response to knife crime, it has to be over the long term and not just one- and two-year funding for projects.
“It is a societal problem which will continue unless it is addressed properly.”
The two murder investigations will again prompt discussion about the possible causes of youth violence, with experts suggesting this includes a rise in the number of children who are vulnerable, increased pressure on services such as policing, and social media fuelling conflict.
Anthony King, chairman of the MyEnds programme which aims to tackle knife crime in London, told reporters at the scene in Croydon: “Sadly it’s because we’re having a lot of breakdowns in schools, in education, young people are being excluded too quickly, some for minor incidents, there’s breakdown in the homes.
“Parents – if you see a bread knife or bun knife missing from the home, please speak to somebody, please contact an agency or an organisation and let the teachers know.”
London Mayor Sadiq Khan said he was “devastated” by the double tragedy.
He said: “I refuse to accept that the loss of young lives is inevitable and will continue to be relentless in taking the bold action needed to put an end to violence in our city.”
Alex Murray, Metropolitan Police commander for specialist crime, said tackling violence is an “unambiguous number one priority” for the force.
The commander told BBC Radio 4’s PM programme: “It is an unambiguous, number one priority of the Metropolitan Police to get violence down, and I think our plans…are focused absolutely on that. We are tackling the causes: money, drugs, guns. We are taking 400 knives a month off the streets.
“But at the same time we are trying to build trust… getting into schools, working with communities who have a credible voice in their community, and I think we are seeing the dividend of that.”
He said social media was also playing a part.
“There is probably three things intersecting to drive that, and one of them is the changing drug market and the emergence of county lines that the Met has treated really seriously, over 1,000 people arrested for county lines.
“The second area is that the trend for young people to carry knives is ubiquitous, and that is why we are out there taking knives off the street all the time.
“And then the third area is the credibility associated with getting onto social media, Snapchat, Telegram, YouTube, and insulting people in an adjoining area and giving them the ‘come on’, and the only credible way people think, often young boys think, is to exert violence to gain their credibility back.
“And those three things all intersect to create this issue, I think.”
Scotland Yard said police were called to the Croydon stabbing shortly after 7pm.
They gave first aid to the boy before the ambulance service arrived but he was pronounced dead a short time later.
Police were called to the stabbing in Yiewsley shortly after 7.30pm, where they found the 16-year-old victim suffering from a puncture wound.
He was also declared dead at the scene.
The victims’ family members have been informed but neither boy has been formally identified, Scotland Yard said.
Post-mortem examinations will be held later.