[Quote:]

Video footage of Osama Bin Laden urging Jihad against the West was found on the laptop computer of a man accused of terror charges, his trial has heard.

Computer expert Michael Dickson, 42, told the High Court in Glasgow he found the files “hidden” on a laptop seized from student Mohammed Atif Siddique.

[..]

Earlier in his evidence, Mr Dickson said useful evidence may have been destroyed when the laptop was switched on by a Special Branch detective before being passed to analysts, against standard police procedure.

All “evidence” from this computer is suspect:

[Quote:]

3 years ago [2000?] the Association of Chief Police Officers (ACPO) set four simple guidelines on Computer Evidence. These establish the basic principles of acquiring evidence from computer systems and are now accepted by the courts in the United Kingdom (and elsewhere).

* Principle 1: No action taken by the Police or their agents should change the data held on a computer or other media.
-Where possible computer data must be ‘copied’ and that version examined.

* Principle 2: In exceptional circumstances it maybe necessary to access the original data held on a target computer.
-However it is imperative that the person doing so is competent and can account for their actions

* Principle 3: An audit trail must exist to show all the processes undertaken when examining computer data.

* Principle 4: The onus rests with the person in charge of the case to show that a computer has been correctly examined in accordance with the law and accepted practice.