A group of friends and family have been found guilty over the death of a teenager caught up in a toxic love triangle.
Trainee plumber Daniel Grogan, 20, became obsessively jealous after finding out 18-year-old Jay Sewell was seeing his ex-girlfriend Gemma Hodder, also 18.
He sent hundreds of texts and WhatsApp messages threatening to kill his rival, rape his mother and petrol bomb his home, the Old Bailey heard.
Grogan also visited trainee accountant Ms Hodder’s house armed with a kitchen knife and threw her on the floor, jurors were told.
She escaped and locked herself in her car as neighbours came to her rescue.
Prosecutor Timothy Cray QC said Grogan had poisoned his friends and family against Mr Sewell ahead of a stand-off near their home in Eltham, south east London.
On December 11 last year, Ms Hodder drove from Kent to see Grogan, accompanied by Mr Sewell and some of their friends, who had a baseball bat.
The level of aggression and violence used on a London residential street was terrifying, and witnesses described the scene as suchAisling Hosein, CPS
Grogan and his group armed themselves with knives, hammers, a 4ft fireman’s axe and wooden sticks and went to confront them, jurors heard.
Jurors were shown CCTV footage of the group battering Mr Sewell’s car with weapons and chasing his friend, Charlie Pamphlett, now 19, who was stabbed in the back but survived.
Mr Sewell was fatally stabbed through the car window by Grogan’s friend Charlie Dudley, 25, jurors were told
Dudley, who lived a few doors from the Grogans, denied murdering Mr Sewell, injuring Mr Pamphlett and violent disorder.
A jury which deliberated for more than 56 hours over 11 days cleared him of murder but found him guilty of manslaughter, wounding with intent and violent disorder.
Daniel Grogan was found guilty of murder, wounding with intent and violent disorder.
His father Robert, 54, was found guilty of manslaughter, wounding with intent and violent disorder.
His mother Ann, 54, was found guilty of manslaughter and violent disorder to angry cries of “You are joking” from her relatives in the dock.
Sister Francesca, 29, was convicted of violent disorder by a majority of 10 to two but cleared of the other charges.
Cousin Liam Hickey, 19, was cleared of murder but found guilty of wounding with intent and violent disorder.
Jamie Bennett, 31, and a 17-year-old boy were convicted of violent disorder.
They were armed with various weapons such as knives, hammers and a large axe – and were all ready for serious violenceAisling Hosein, CPS
The victim’s family gasped “Yes” as they held hands and supported each other in court.
It was claimed Dudley had been encouraged and helped the Grogans and other friends who were embroiled in the feud against Mr Sewell.
But it was alleged on behalf of the defendants that they had armed themselves, fearing that they would be attacked in their home by Mr Sewell’s friends.
Giving evidence, Robert Grogan admitted having an axe but said he was unaware that anyone was carrying a knife.
He told jurors he saw Dudley deliver what he thought were “two or three punches” as he stood behind him.
He said: “It just happened quickly and then it was finished.”
He was later surprised to learn that blood had been found on his jeans as he did not see a knife, the court heard.
Robert Grogan said his son Daniel had never told him he had been making threats.
The 17-year-old defendant admitted being armed with a stick but said he got “scared” and ran away before the stabbing.
The young boxer, who cannot be identified because of his age, said: “I thought these people would bring weapons with them so I got given it. If someone attacked I could use it in self defence.
“It had a tea towel wrapped around it to take some of the impact out. I did not want to cause no harm to anyone. It was not my intention.”
None of the other defendants gave evidence but it was claimed on Dudley’s behalf that Robert Grogan was covering up for a family member by naming him as the stabber.
However, jurors heard Dudley had been picked out by Ms Hodder in an identity parade and his DNA was found on the handle of a kitchen knife found near Grogan’s home.
It was alleged Francesca Grogan and Jamie Bennett were carrying hammers wrapped in towelling, Ann Grogan had a kitchen knife and Hickey had a wooden baton.
Following the verdicts, the defendants were remanded into custody to be sentenced on a date to be fixed.
Aisling Hosein, from the CPS, said: “Several members of the Grogan family and some of their friends were lying in wait for the deceased and his friends.
“They were armed with various weapons such as knives, hammers and a large axe – and were all ready for serious violence.
“The level of aggression and violence used on a London residential street was terrifying, and witnesses described the scene as such.”
Detective Chief Inspector Simon Harding, of Scotland Yard, said: “This was a premeditated attack. It was quick, vicious and incredibly cowardly.
“Having armed themselves with deadly weapons, they attacked Jay and his friend like a pack of wolves and they knew their plans would have horrendous consequences for anyone standing in their way that evening.”
Mr Sewell’s mother Sharon Louch said in the family’s impact statement: “It breaks my heart to know that Jay will never be able to fulfil his dreams.
“He is my first thought when I wake up and last before I go to bed. I try my hardest to shield my children from the pain, but I can’t do it. They all know they will never see their brother again.
“It’s been nearly 10 months since that day in December, each one proving as hard as that before it. The trial lasted for what seemed an eternity, I pray I never have anything to compare it to.
“There is no sentence this court or any other can pass which can come close to healing the pain or make up for not being able to look at my Jay’s face or hear him laugh. I haven’t come here expecting or wanting it to.
“However it does provide a glimmer of hope that those responsible have been held to account for their actions.
“Jay you were a blessing and made us proud from the day you came to us until the moment you were taken.”