A City lawyer was stabbed to death just yards from his home by two men who had already robbed him.
Mr Pryce had been out with friends
Police said Tom ap Rhys Pryce, 31, was first mugged in Bathurst Gardens, Willesden, north-west London, on Thursday night.
The robbers then attacked him again and stabbed his body, hands and head.
Officers think the men, who are black and in their late teens or early 20s, may have been hurt as Mr ap Rhys Pryce had "clearly tried to defend himself".
Det Supt Julian Worker said: "I believe he had been robbed, and then they went on to gratuitously and unnecessarily stab him to death."
Mr ap Rhys Pryce worked as a litigation lawyer for Linklaters and it is thought he had been out with colleagues in the City.
Police said he left at about 2250 GMT and called his fiancée to let her know he was on his way home.
It is understood he caught the train to Kensal Green station then walked up College Road into Bathurst Gardens where he was subjected to a "ferocious" attack.
The victim was found at about 2345 GMT and pronounced dead soon after in hospital.
Det Supt Julian Worker, said: "This was a particularly vicious and gratuitous attack... due to the nature of this attack it is quite possible that one or both the suspects may have sustained injuries during the attack.
"I would particularly appeal to anyone who may have treated such injuries or anyone who knows of someone having sustained injuries to come forward".
John Turnbull, head of litigation at Linklaters, said he and his colleagues were shocked by the news.
"Tom was a good friend and colleague and we will miss him very much."
Both ends of the quiet residential street, full of mainly Victorian terraced houses, remain sealed off.