A man has been arrested over the killing of a father-of-three who was stabbed on his doorstep.
The man stabbed in Bristol was returning from an anti-crime event
The 30-year-old, from Knowle West in Bristol, is being held at a police station in the city on suspicion of the murder of Barry Wilson.
Mr Wilson, 29, died after he was knifed outside his home in Ilminster Avenue, Knowle West, on Tuesday afternoon.
The incident is one of several stabbings during a five-week national knife amnesty.
The initiative, which began last week, allows knives to be handed in at police stations without fear of penalty.
Secure bins are being placed in public reception areas of most police stations in an effort to encourage people to hand in their weapons.
And police have said that once the amnesty is over, tough action will be taken on those found armed with knives.
Mr Wilson's partner Maxine Prescott is pregnant with the couple's fourth child.
The victim of a stabbing in Nottingham on Sunday, 26-year-old Ian Montgomery, is in a critical but stable condition at a city hospital.
Mr Montgomery was trying to prevent a woman being attacked
Police praised Mr Montgomery, who was knifed when he stepped in to stop a woman from being attacked.
Although some tragic incidents have been highlighted in recent days, Home Office figures suggest fatal stabbings have fallen in the past few years, although there are no figures for knife attacks overall.
But Deputy Chief Constable Andy Trotter of the British Transport Police said his officers were sufficiently concerned about the use of knives, especially in robberies, that it launched an intelligence-led operation two months ago.
And his officers seized 90 knives and weapons on Monday when visitors to Luton Carnival were screened using metal detectors as part of Operation Shield.
"This is a perfectly legitimate area of public and press concern," he said.
Marian Fitzgerald, a professor of criminology, told BBC Radio Five Live that while the statistics are not conclusive, there is a perception that knife crime is on the increase.
"There are no hard figures, like the figures for firearms, to show whether it's going up or down, or indeed to show whether interventions like the amnesty are making any difference. "My own sense from doing work is that this has been a steadily growing problem, particularly among young people."
The Violent Crime Reduction Bill, making its way through Parliament, would increase the age at which a person can be sold a knife from 16 to 18, and give head teachers powers to search pupils for weapons, she said.