A 16-year-old boy has died in the fifth fatal suspected stabbing in London in a week.

The victim was found with suspected stab wounds in Tulse Hill, south London, after police were called to reports of a shooting in Greenleaf Close at 10.53pm.

Paramedics tried to save the boy but he was pronounced dead at 11.41pm, the Metropolitan police said as it opened a murder inquiry. Officers believed the boy had stab rather than gunshot wounds, though the Met stressed that inquiries were at an early stage. No immediate arrests were made and next of kin have been informed.

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The suspected murder would bring the number of homicides in London this year to 117. On Monday the London mayor, Sadiq Khan, said it could take a generation to turn the tide of violent crime in the capital. Last Wednesday, “adored” father Rocky Djelal, 38, was fatally stabbed in broad daylight in Southwark Park in Rotherhithe, south-east London.

The following day 15-year-old Jay Hughes was killed in Bellingham, also in south-east London, by a stab wound to the heart.

Malcolm Mide-Madariola, 17, was fatally knifed on Friday outside Clapham South tube station, south London, near where he studied. On Sunday a man believed to be aged 22 was fatally stabbed in Samos Road, Anerley, also in south London.

A neighbour in Greenleaf Close, Tulse Hill, thought she heard a gunshot before dashing outside and finding the teenager in a driveway, looking like an “angel”.

Paulina Wedderburn saw the victim’s emotional mother and father at the scene and said it it took some 15 minutes for emergency crews to arrive. “The boy was laying down. He looked like an angel, like he was sleeping,” Wedderburn said on Tuesday morning. “I just feel sorry for the mum. The mum’s screams I can’t get out of my head. It’s awful. Imagine being a mother seeing that.”

The neighbour saw a black car driving off. “A big black Audi, I think,” she said. Wedderburn, who has lived in a flat in Greenleaf Close for decades, lamented the recent spate of violence and killings in south London, saying it had not always been that way.

“What’s going on? What is it? Why do they have to be killing each other?” she said.

“When I was growing up in the 70s, if there was a fist fight, that was it. There was no knives. All you’re doing is upsetting families. If you saw the mum and dad, it was heartbreaking.”

She added that the victim’s mother had been to the flats before to pick up her son as she did not like him hanging around there.