Source: A YouTube video posted by user "tatermoog."
What we heard: During the Electronic Entertainment Expo in June this year, Sony unveiled the Sly Collection, a remastered version of three Sly Cooper titles for the PS3. The original series of stealth platforming games featuring a thieving raccoon were developed for the PS2 by Sucker Punch Productions.
In October, Sony released further details about the collection, announcing it would ship in North America on November 9 and include updated versions of the three original Sly Cooper titles--Sly Cooper and the Thievius Raccoonus, Sly 2: Band of Thieves, and Sly 3: Honor Among Thieves--remastered with 720p visuals, as well as 3D support, trophy incorporation, and a range of PlayStation Move-enabled minigames.
Now, it appears Sucker Punch's plans for the series extend beyond the high-def compilation. YouTube user "tatermoog" posted a clip on the site allegedly showing a teaser trailer for Sly Cooper 4 embedded into the recently released Sly Cooper Collection. According to his post on YouTube under the video, "tatermoog" found the trailer after finishing off all the trophies in the collection. He used his own video camera to record the trailer and post it on YouTube. The trailer ends with a Sly 4 logo and a question mark underneath it.
The official story: Sony Computer Entertainment Australia (SCEA) acknowledged that the matter was purely speculative for the moment, and thus declined to provide an official comment.
Bogus or not bogus?: Probably not bogus. Sucker Punch's Brian Fleming has previously stated in interviews that the return of Sly is something that will be likely to happen. Sucker Punch has also teased a fourth installment in its last game, Infamous, with movie marquees in Empire City listing "Sly Cooper 4."