The Big Issue has confirmed that two men who were stabbed to death in Birmingham city centre worked as vendors of the publication.
The magazine's founder and editor-in-chief John Bird said: "Myself and everyone at The Big Issue has been deeply saddened to hear the tragic news that two of our well-liked Birmingham based vendors were stabbed to death in the city centre.
"We are struggling to make any sense of this utterly senseless attack, and our sincerest condolences go out to the families of the victims.
"This awful crime, perpetrated against two hard working, mild mannered men, only serves to illustrate the extreme vulnerability of people who live and work on the streets."
The two men, who were in their thirties, were attacked just before 6pm on Friday in front of "potentially hundreds of witnesses".
One victim is thought to have been stabbed outside a Sainsbury's store in Martineau Place, while the other was found slumped near a Boots store in Union Street with fatal injuries.
Officers administered first aid on both men, but both were pronounced dead at the scene.
Kevin Blake, 52, who was leaving work at the time, told Sky News: "There was someone lying on the ground with a police officer pumping his chest and someone holding a white compress on his lower abdomen and someone sort of incubating him.
"He was in a very very bad way. As I walked to the train station there was huge droplets of blood for about 30 or 40 yards, which signified that he was very, very seriously injured.
"It was a surprise to read in the paper that two people had been stabbed and not just the one that I saw. It was quite a sight."
A man was arrested in New Street near the Odeon Cinema minutes after the stabbings.
Police confirmed a 23-year-old man is being questioned on suspicion of stabbing the two men to death.
Inspector David Keen said: "Two men have suffered fatal injuries - these have been inflicted in the heart of the city at a busy time when workers and shoppers would be heading home.
"There are potentially hundreds of witnesses, either people who saw the stabbings or the offender leaving the scene, and I'd urge people to get in touch immediately - they could have vital information."
Forensics and search experts cordoned off several scenes in and around Union Street to preserve evidence. Those cordons have now been lifted.
A spokeswoman for West Midlands Ambulance Service said: "Crews arrived to find two men who had been stabbed and were being given excellent first aid by police officers and passers-by.
"Both men went into cardiac arrest. Crews and the team of medics administered advanced life support to both men but, sadly, despite the best efforts, nothing could be done to save them and they were confirmed dead on scene."
Post-mortem examinations on the two victims are due to take place to determine the exact cause of their deaths.
Police said they were mounting "extra reassurance" patrols in the area.
:: Anyone with information is asked to call police on 101.