She vanished aged three whilst on holiday in Praia da Luz in 2007.
Now Scotland Yard officers have travelled to Portugal to speak to a group including a British man and woman.
It's after police in the UK opened an investigation into the case.
Detectives are said to have at least three suspects they wish to interview.
The Metropolitan Police's 'Operation Grange' has been given permission to come to Portugal by police there who have also started looking into the case again.
After Madeleine disappeared her parents turned to their Christian faith for help and attended several church services whilst still in Portugal.
In 2007 Kate and Gerry McCann met Pope Benedict and had a picture of the toddler blessed.