A fourth man has been arrested on suspicion of murdering a woman who vanished in south London last month.
Student nurse Owami Davies, 24, was captured on CCTV in the company of a man on Derby Road, Croydon on 7 July – the night she was last seen alive.
The Met Police has been granted extra time to question three other men, aged 23, 27 and 32, previously arrested on suspicion of murder.
Detectives insist the case remains a missing person investigation.
The fourth arrest, a 22-year-old man, remains in custody after being detained at an address in Croydon on Wednesday evening, Det Ch Insp Nigel Penney said.