A woman, a seven-month-old baby and a five-year-old boy have been found dead in an apparent murder-suicide.
Early reports suggest the 33-year-old may have killed the two boys before killing herself in Harrow, north-west London.
Police discovered their bodies after going in to the property at 5.20pm yesterday.
According to neighbours, the mother was Sri Lankan and married to an accountant.
The children's deaths are being treated as murder but the woman's death is not being treated as suspicious.
Scotland Yard said police are not looking for anyone else in connection with the incident.
Officers were called by London Ambulance Service to the address in Woodgrange Close following reports of a woman and two children with injuries.
When they arrived, the three were pronounced dead by medical staff. Their next of kin have been informed.
A post-mortem examination on the woman was taking place this afternoon.
A spokesman for Scotland Yard said: "Officers were called at approximately 1720hrs on Thursday, 9 January by London Ambulance Service to an address in Brent to reports of a woman and two children with injuries.
"When officers arrived, the three were pronounced dead at the scene by medical staff.
"The deaths of the two children are being treated as murder; the woman's death is not being treated as suspicious at this stage.
"Detectives are not seeking anyone else in connection with the incident."