Five teenagers face years in jail after stabbing a man to death as he returned home from a hospital appointment with his pregnant partner.

Daniel Frederick, a 34-year-old father of four, was set upon by a group of youths who stabbed him repeatedly yards from his front door in Stoke Newington, north London, on 8 January.

It is believed Frederick was the innocent victim of violence involving youths from nearby estates.

One of his attackers, aged 16, had sought revenge after his friend was attacked in prison by the local Shakespeare Boys gang, the Old Bailey heard. The boy, who cannot be named for legal reasons, pleaded guilty to Frederick’s murder.

Kacper Karasinski, 19, from Hackney, and a 17-year-old boy were found guilty of murder on Tuesday.

Yigiter Gok, 18, of Stoke Newington, and another 17-year-old boy were found guilty of manslaughter by a majority of 11 to one.

All but one defendant – a 17-year-old boy – had previous convictions for carrying knives, dating back to 2016.

Daniel Frederick. Photograph: Metropolitan police/PA

The prosecutor, Allison Hunter QC, told jurors during the trial that Frederick was killed in a “deliberate, ruthless, violent attack”. Witnesses saw the “sinister and intimidating” youths wielding knives as they walked purposefully towards Frederick, wearing dark clothes, hoodies and masks.

Hunter said: “It lasted no more than a few seconds, during which Daniel Frederick received seven stab wounds to his back, buttocks and thighs. The fatal stab wound was to the left side of his back, approximately 11.5cm (4.5in) deep, passing between his sixth and seventh rib.”

Afterwards, the young men were picked up on CCTV as they ran towards the Hill Court estate in Hackney, shedding clothes as they went.

Three knives were retrieved by police, although the prosecution could not say which were used in the attack. However, a pathologist confirmed that more than one knife would have been used to stab Frederick.

Within an hour and a half of police issuing a public appeal, Karasinski booked a flight to Oslo, but was arrested at the airport. Gok fled on a ferry to France and travelled on to Turkey before returning to the UK in March. He later admitted being at the scene of the murder, but denied taking part.

Giving evidence, Gok said the 16-year-old boy had been angry that a friend of his had been beaten up in jail by one of the Shakespeare Boys.

None of the defendants reacted as the jury delivered its verdicts after nearly 15 hours of deliberations. They were remanded in custody to be sentenced at a later date.

DI Paul Considine, from the Metropolitan police, said: “This was a ruthless, violent and unprovoked attack in which Daniel stood no chance. He was completely taken by surprise by his attackers, who cowardly stabbed him in the back, giving him no opportunity to defend himself.

“All five defendants disguised and armed themselves and willingly carried out a brutal attack on Daniel, knowing it was likely there would only be one outcome, the infliction of very serious injuries or death.

“This was a complex investigation made more difficult as Daniel was mistakenly targeted by his attackers. My team diligently pieced together the evidence and then located, arrested and charged all those responsible for his death.

“I am delighted that the jury has convicted the defendants and hope it provides Daniel’s family with a small measure of comfort and closure.”