Open source means information available to anyone, not just police officers. I typically use six websites for graffiti investigations:
Detective Michael Bazzell of the Alton, Illinois, Police Department has an exhaustive list of every possible website you could use for investigations at his web site, Intel Techniques.
Flickr is a popular place for professional and serious amateur photographers to share their work. Casual photographers typically share photographs on Facebook and only use Flickr if anonymity is sought, as there is no requirement to use a real name to create a Flickr account. The anonymity of Flickr has made it popular with graffiti vandals. The majority of photos of graffiti on Flickr are posted by people who did not write the graffiti. They simply enjoy photographing street art and call themselves “graffiti hunters.” However, if a Flickr user is only posting a certain graffiti tag, this person is likely responsible for the graffiti.
User Name Search
People tend to use the same username on different websites.You might be able to find the Flickr username on other websites using Usernamecheck or Google. This, in turn, could lead you to a real name.
Examples
plusruss
daki