Malware Analysis Scenario: A notorious criminal, Donald Dodger has been suspected of being involved in unsavoury pornography style activities and has

A notorious criminal, Donald Dodger has been suspected of being involved in unsavoury pornography style activities and has been arrested in a recent raid by Wensleydale CID. During the raid, scenes of crime officers recovered his local desktop PC.
The PC has been forensically imaged by another investigator and an unusually high level of illegal images have been found on the hard drive. Donald has been arrested and charged on the strength off the evidence found on the forensic hard drive image with bestiality.
Donald’s defence team have suggested that Donald is very non computer literate and he thinks that his computer had been deliberately infected with malware that has downloaded this incriminating evidence off the Internet without his knowledge.
Your task is to take the forensic image of the suspects PC and investigate what Malware is present and is there any evidence that may suggest if any of the malware found could be responsible for the defence suggestion.
You need to remember that you are reporting what you have found within the remit given and any conclusions must be based on fact. Concise details are required because there is a maximum of 1000 words available.