Detectives investigating the fatal stabbing of Hasan Ozcan in Barking have made a fourth arrest.
On the morning of Thursday, 22 February a 20-year-man [D] was arrested in Hackney on suspicion of murder. He was taken to an east London police station where he remains in custody.
Officers continue to appeal for information following the fatal attack.
Police were called at approximately 22:10hrs on Saturday, 3 February, to reports of a stabbing in Abbey Road, Barking.
Officers attended along with London Ambulance Service and found a 19-year-old man, Hasan Ozcan, suffering from stab wounds.
Hasan, who was from the Barking area, was pronounced dead at the scene at 22:55hrs.
A special post-mortem examination took place on Tuesday, 6 February at Queen's Hospital Mortuary and gave the cause of death as multiple stab wounds.
On the morning of Friday, 16 February, a 15-year-old boy [A] and a 19-year-old man [B] were arrested at addresses in Dagenham and Hornchurch on suspicion of murder. On Wednesday 21 February, a 18-year-old man [C] was arrested in Barking on suspicion of murder. They have all since been bailed to return on a date in mid-March.
Detectives from the Homicide and Major Crime Command (HMCC) are investigating and are continuing to appeal for information.
The investigation is being led by Detective Chief Inspector Larry Smith. He said: "We have now made four arrests but we are still appealing for information so we can establish the circumstances which led to a young man losing his life.
"It is vital that those out there with information who haven't yet done so contact the police. I'd urge you contact the incident room as soon as possible. Your call will be treated in the strictest confidence."
Any witnesses or anyone with information that may assist the investigation should contact HMCC officers via 020 8345 3985.
To remain anonymous call Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.
You can also tweet information to police via @MetCC.