Four different groups of tourists were allowed to stay in the flat before forensics officers attempted to take blood and DNA samples from the rooms.
The resulting DNA analysis was inconclusive and laboratory scientists said samples were badly degraded and contaminated.
Potentially crucial evidence from the two-bedroom apartment in the Ocean Club complex may have been lost forever.The gaffe was revealed in the Maddie case files made public this week. It was one of a series of blunders by Portuguese police, who were finally forced to shelve the investigation last month because of a lack of evidence.
Their slapdash approach to sealing off apartment 5A, the crime scene, is in stark contrast to the effort they made to link Kate and Gerry McCann to their daughter's disappearance.
It lay empty for a month but cleaners were allowed inside and it was then rented to holidaymakers until August.The two-bedroom flat was only permanently sealed off when specialist sniffer dogs were taken inside in August and supposedly detected minute traces of blood and the 'scent of death'.
Their reaction prompted forensics officers to take further samples from the flat, three months after the events they were investigating.
Details of all those who stayed in 5A after the McCanns were revealed in the case files.
On June 12, a couple from Liverpool moved in for a week, followed by a family of four from Falkirk in Scotland.
Next, a couple from New Barnet, Hertfordshire, rented the flat and on July 19 a family of three from Leicester moved in for a week.
It was not clear if they were told of the flat's history, but the apartment was the focus for much of the early media attention and was shown in newspaper photographs and television reports around the world. (Daily Mail Saturday 9th August 2008)
