Scientists in Israel have successfully demonstrated that it is possible to fabricate DNA evidence. Dan Frumkin lead author of a paper published in the journal of Forensic Science indicates that you could "Engineer a crime scene....
Bert from Sesame Street is evil and this site has the photo evidence. Sadly this site has been taken down but the internet archive has such great pics as Burt's mug shot, Burt at the JFK assasination and more.