This article is about terrorism and ISIS, but of course, they had to mention child porn too.

Every time the press or the FBI mentions "terrorist", the word "child porn" is not far behind.

The part about child porn is this one:

How anti-Islamist spies go digital in battle against terrorism

[...snap...]

Even when criminals take care to mask their location and identity, “a determined investigator can find that you interact in a unique way,” such as the rhythm with which a person taps keys on a keyboard, said Alex Holden of Hold Security, a consultancy in Milwaukee, Wisconsin.

Similarly, in efforts to identify the provenance of images of children being sexually abused, the U.S. government has sought the advice of botanists and ornithologists to identify locations based on background details – skills similar to those the FBI and other agencies have used to identify individuals in ISIS videos

Full article:
http://www.dailystar.com.lb/News/Middle-East/2014/Oct-17/274356-how-anti-islamist-spies-go-digital-in-battle-against-terrorism.ashx#axzz3GqMZghDg