Cleo Smith, the four-year-old Australian girl who was kidnapped, has told police a woman would come to her accused kidnapper's house to brush her hair and dress her.  

Investigators are now travelling back to the area to see if another person was indeed involved.  

So how hard is it to interview a four-year-old who's gone through a hell of a lot, and how reliable are the memories and information? 

Ggeorgina Heydon, an associate professor in Criminology and Justice Studies at the Royal Melbourne Institute of Technology joined Heather du Plessis-Allan to provide some detail. 

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