Several forums, including those published by Giantbomb, GameTrailers and French website Gamekyo, are reporting that Sony's US Playstation website published a post disclosing Syphon Filter 4 before removing it an hour later.
Apparently, the post said the game was being developed using a new engine by SCE London and would be releasing in Q4 2012.
We decided to do some snooping around and it appears Sony has registered not one but five Syphon Filter related domains. The domains are SyphonFilter-Game.com, SyphonFilterAgency.com, SyphonFilterCommand.com, SyphonFilterHq.com and SyphonFilterOps.com.
Chances of an E3 reveal just went up. We'll send Sony an email and ask for comment.