A 15-year-old boy stabbed to death in London has been named.

Jermaine Goupall was the second teenager to be killed in a knife attack in the capital in less than 24 hours – and the 15th so far this year. A murder investigation has been launched after the latest incident, which took place in Thornton Heath, south London, on Tuesday night.

His family, gathered in their family home a short distance from the scene in Georgia Road, said they were too upset to talk. A crime scene tent remained in place on Wednesday afternoon while uniformed officers kept guard at the edge of the cordon in heavy rain.

A neighbour who knew Jermaine said: “He was a nice lad. I would see him to speak to in the street and he would come over and stroke my dog, say hello. I know his dad, Stan, better. It seems desperately sad that this can happen to such an innocent boy.”

Other shocked locals, including youngsters gathered near the scene, said they believed the death to be gang-related.

Another, Nadir Sheikh, who lives opposite the road where the stabbing took place, said: “There are always a lot of kids hanging around in groups here. There was another incident here a few weeks ago so the police came around then too. I think there needs to be more police presence, surveillance, a way to stop this happening.”

The victim – who has not yet been formally identified by police – was pronounced dead at the scene shortly before midnight.

The death follows the fatal stabbing of a 19-year-old man in Peckham, south-east London, in the early hours of Tuesday.

Police were called to a disturbance in Old Kent Road at about 2am and detectives believe the victim was involved in an altercation involving a large group of people outside a nearby venue.

Six people were arrested on suspicion of murder, although three have been released with no further action taken against them, while two were released pending a police investigation. The sixth person remains in custody.

Witnesses have spoken of seeing the teenager “being mobbed” by a crowd.

He was pronounced dead at the scene at 2.50am.

Postmortem examinations are due to be held for both teenagers. Detectives from the Metropolitan police’s homicide and major crime command are investigating both murders.

The stabbings follow a spate of knife attacks in the capital this year, which has seen more than a dozen victims suffer fatal or serious stab wounds.

The number of children and teenagers killed in England and Wales between January and July this year by violence involving knives was 21.

Knife crime jumped by 20% to 34,703 incidents – the highest level for seven years – in the 12 months to March, according to the latest official crime figures. The largest increase in knife crime came in London, which accounted for 40% of the rise.

