Two boys aged 16 and 17 arrested on suspicion of murder on Saturday were today bailed to dates still to be fixed, while a 18-year-old man arrested on suspicion of murder on Saturday remains in custody.
A 20-year-old man was also arrested on suspicion of murder last Thursday and was bailed until late March.
Officers were called to reports of a youth stabbed in Lupus Street shortly before 7pm on January 27.
The teenager, who lived on the nearby Churchill Gardens estate, was taken to King's College Hospital but died later.
A post-mortem examination gave the cause of death as multiple stab wounds.