Police launched a double murder inquiry on Sunday after a 41-year-old man and a seven-year-old girl, believed to be his daughter, were shot in north west London.
Scotland Yard said the pair were found suffering from gunshot wounds in a bedsit early this morning. Both later died in hospital from their injuries.
"Police are keeping an open mind about the motive, though suicide has been eliminated. Several lines of inquiry are being followed," a Scotland Yard spokesman said.
Police said neither victim had been formally identified.