John Blackburn was convicted yesterday of murdering his sister's boyfriend Cole Wilson with akitchen knife.
The 20-year-old bled to death within minutes from knifewounds to the head and chest.
It happened at Blackburn'sgirlfriend Kim McGuire's house at SledmereClose in Peterlee last September.
Blackburn's sister Jade cried as she described how Cole said "I love you" and kissed her before he died.
The court heard that Jade was staying at the house with her boyfriend of three years when the pair started arguing.
Prosecutor Mark Giuliani told the court that when the noise continued into the early hours, Blackburn said "I'm going to stab him."
Jade Blackburn told jurors she saw her brother throw a punch at Cole but that she didn't see a knife. She said, "I remember Cole was on the settee, he had his hands on his head and he said 'I've been stabbed."**
Blackburn, of Holywell Avenue, Walker, denied murder. He told the court Cole had been his "best mate" and that he had not meant to stab him.
But at court a jury found him guilty of murder. Adjourning the case until next month Judge Paul Sloan said "There is only one sentence to be passed in your case and that is a sentence of custody for life."**