A woman remained in police custody on suspicion of murdering her two babies just days after the family moved into a £1.2 million home.
The 10-week-old boy and his 14-month-old sister, Lily Sky Boots, were discovered unconscious by their father, Jeff Boots, when he returned home from work, sources said.
Police arrested their mother Felicia at the semi-detached home in south-west London, after emergency services were unable to revive the children at the scene on Wednesday night.
Detectives suspect she smothered the babies while suffering from post-natal depression.
Watch this report from Paul Brand