West Midlands Police has praised the public response in assisting officers with their inquiries, after the stabbings in Birmingham on Friday evening.
All cordons have now been lifted from the scene on Union Street.
– Detective Inspector Buck Rogers, West Midlands Police
"We have had a fantastic response from the public so far and their information has proved vital to our investigation."
"Early inquiries suggest that this wasn't random. The attacker appears to have known his victims.
"Our inquiries continue and if there is anyone who saw something on Friday evening and hasn't yet come forward we urge them to call us now on 101."
Police have identified the two men who were stabbed to death in Birmingham on Friday.
Wayne Lee Busst, 32, and Ian Watson Gladwish, 31, were both Big Issue sellers based in the city centre. They were stabbed just before 6pm.
A 23-year-old man arrested on Friday evening remains in custody. A warrant of further detention was issued this morning, allowing officers to question the man until 21.00 tonight.
The Big Issue has confirmed both stabbing victims were sellers of the publication.
In a statement, founder and Editor-in-Chief John Bird says he and his staff are deeply saddened.
"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 yesterday evening.
"We are struggling to make any sense of this utterly senseless attack, and our sincerest condolences go out to the families of the victims.
– John Bird, The Big Issue founder and Editor-in-Chief
"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. Which is why we at the Big Issue are constantly striving to create opportunities which will help our vendors to get off the streets and out of harms way.
"We are truly devastated that these two individuals have been deprived of just such a future."
Union Street in Birmingham City Centre has now re-opened following the incident last night. investigations are ongoing
Police renew appeal for witnesses following double stabbing in Birmingham city centre last night http://t.co/Zu56eAHP
Superintendent Richard Moore from West Midlands Police.
Officers have arrested a man in connection with #Birmingham centre stabbing - arrested in New Street minutes after police received reports