South-East London Area Commander Neil Basu said: 'It is important that we explain more about the circumstances of the searches.
'Four scene examinations were conducted of the property. The first followed immediately from the missing person report that was received on Friday 4 August. An initial visit was made to assess the situation and examine the property. This visit was not regarded or viewed as a full search of the property.
'The second visit was a full search of the property with the consent of the occupiers. This was conducted on 5 August over a period of two hours. All parts of the premises were searched including the location where a body was discovered, five days later, on Friday 10 August.'
'An early review has been conducted and it is now clear that human error delayed the discovery of the body within the house. We have apologised to Tia's mother that our procedures did not lead to the discovery of the body on this search.'
'A third visit was undertaken on 8 August. This was not a search, but the attendance of a body recovery dog to assist the investigation team in their enquiries.
'It is not appropriate to comment further on aspects of the criminal investigation currently being conducted but our investigation was such that it was decided that a further intrusive search needed to be undertaken - it was that search, yesterday, which resulted in the discovery.
'On behalf of the Metropolitan Police I apologise for the distress and concern this delay will have caused.'
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