A 24-year-old woman has died in hospital after a double shooting while out celebrating her birthday, police said.
Sabrina Moss, of Edgware, north London, who was gunned down early on Saturday, is believed to have been caught in the wrong place at the wrong time, a senior officer said.
Detective Chief Inspector John Sandlin of the Metropolitan Police said: "Inquiries continue to establish the full circumstances of this tragic incident.
"At this early stage, I believe the two women were innocent parties who were caught in the wrong place at the wrong time."
Another 24-year-old woman is in hospital. Her injuries are not thought to be life-threatening.
Scotland Yard said officers were called at 4.12am to reports of shots fired in the street in Kilburn High Road, Kilburn, north west London, at the junction with Messina Avenue. Police and London Ambulance Service found two women suffering from gunshot injuries and both were taken to London hospitals.
Sabrina was pronounced dead later. She had been out celebrating her 24th birthday with friends.
Mr Sandlin said: "I am appealing for anyone who witnessed the shooting, or who saw anything suspicious in the Kilburn area early this morning, to call police. In particular, I need to hear from anyone who saw two males who came into the High Road from Messina Avenue and, after the shooting, made off on foot back along Messina Avenue."
One man has been arrested in connection with the investigation.
Anyone with information that might assist the investigation was asked to call the incident room at Hendon on 020 8358 0300. To remain anonymous, call Crimestoppers on 0800 555 111.