The inquests into the deaths of Michael Pedersen and his two children will be opened and adjourned tomorrow.
A post mortem examination has revealed that seven-year-old Ben and six-year-old Freya died from multiple stab wounds. Mr Pedersen, who was from Chertsey in Surrey, also died from stab wounds to the chest.
Their bodies were found in Hampshire on Sunday.
Police are not looking for anyone else in connection with the deaths.
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The family heirloom was taken after the man was approached by a woman in The Crown pub in Soho.
He was found close to Harrow and Wealdstone station just before 7pm and was taken to a central London hospital.
Darren February broke into Cowell's home as he and his family slept and his security guard used the toilet.