A complete stranger stabbed a man to death in a "brutal.. and entirely unprovoked" attack, a court has been told.
David Hastings, 48, of Norwich, was stabbed 13 times from behind after walking away from Rose Lane car park in the city on 23 June.
Rolands Heinbergs, 23, of no fixed address, denies murder.
Wayne Cleaver, prosecuting at Norwich Crown Court, said the attack was as "unrelenting as it was swift".
Mr Cleaver said Mr Hastings was walking with his friend Karen Althoff at about midnight when he was stabbed by Mr Heinbergs.
The father-of-two suffered wounds to his back, chest, neck, heart, lung, liver and pancreas.
"The injuries caused catastrophic blood loss. Any one of these injuries could have proved fatal," Mr Cleaver said.
Mr Cleaver said Mr Hastings was a "complete stranger to the defendant" and was "minding his own business".
"He just happened to be in the wrong place at the wrong time," he added.
The prosecutor said Mr Heinbergs, originally from Latvia, was arrested at about 03:45 BST and "the dead man's blood was found on the defendant's hand".
Mr Cleaver said police examined Mr Heinbergs' mobile and found the message: "I killed. If caught will have to go to prison."
"The prosecution say this was cold-blooded murder and we will bring the evidence to prove it," he said.
The jury was shown body-cam footage from Sgt Adam Raynor on the night of the attack when he talked to Ms Althoff, who told him the attacker "did not say anything, he just kept stabbing him".
She added: "He [Mr Hastings] didn't do anything to deserve this."
The trial continues.