ymu
Niall Ferguson's deep-cover sock-puppet
IIRC (and I may not) the timestamps on the CCTV were not accurate and this point has been brought into question. You'll have to do your own digging to check this, but at least some of the dodgy timing evidence has been resolved..
The call was made 15 minutes after 2 postal police came to the house to return mobile phones found in a garden. Knox and Solecitto told them they had "already" called the police (untrue) as there looked to have been a burglary (the staged one). 20 minutes later they actually call the police. They lied to the postal police who surprised them outside the house, which incidentally stunk of bleach from the cleaning.
To make sense of this it needs to be seen in context.