A five-year-old girl remains in a critical condition in hospital after being shot in the chest.
Police are hunting three youths who shot her and a 35-year-old shopkeeper.
The child, understood to be called Thusha Kamaleswaran, is believed to be London's youngest gun crime victim.
The shopkeeper, believed to be Roshan Selvakumar, was shot in the head. The two bystanders were injured while inside Stockwell Food and Wine Shop in south London at 9.15pm on Tuesday.
Police said they remained in a "critical but stable" condition.
They were hit as two black youths cowered in the store after being chased by three other black youths on bicycles. As the pair hid inside, the gunman stopped at the door and opened fire indiscriminately. Police are not sure how many bullets were fired.
The three attackers, who a witness said were aged between 14 and 17, fled as their intended targets chased them on foot from the Stockwell Road shop along Broomgrove Road and into Stockwell Park Estate.
The victims, who police said were Sri Lankan and unrelated, were rushed to hospital in south London.
Detective Chief Inspector Tony Boughton urged witnesses to come forward. He said: "This is a terrible incident where an innocent child has been seriously injured.
"I appeal to those who have information or were involved in this shooting to come forward and assist us with this investigation. These criminals have seriously injured two innocent bystanders and must face the consequences of their actions."