Three teenagers have been arrested on suspicion of murder after a man died after being stabbed in east London.
Syed Jamanoor Islam, 20, died in hospital after an attack in Wager Street, Mile End, on 11 April.
Three youths, aged 18, 15 and 17, were arrested in South Yorkshire and are being held at a London police station.
The victim's father, Syed Abdul Mukit, has called on the community and politicians to tackle the rise in crime in society.
He said: "We lost our first son in his mother's arms and no family ever wants to lose a child in that manner.
"It is about time we as community members stand up against violence, injustice and hate in the community."
A post-mortem examination gave Mr Islam's cause of his death as a stab wound.
He was one of three people stabbed to death in little more than 24 hours in attacks in London.
Officers said they are keeping an open mind about a possible motive.
Police believe the victim was with friends in Wager Street when he was approached by a group of males before an altercation began.
Det Ch Insp Tony Lynes said: "We are still keen to speak to anyone who was in the area at that time and might have seen what happened or who has any information about the circumstances."
An 18-year-old man who was arrested on suspicion of murder on Wednesday has been bailed pending further inquiries.