A keen-eyed Dota 2 player, and terrible tour guest, took a secret snapshot of a computer monitor that lists "Left 4 Dead 3" and "Source 2" as current projects while visiting game developer Valve's offices.

While on a tour of the facilities as part of the International 3 tournament, took a snap of an internal changelog that has the game listed as a project in development. The photo, seen above, looks cryptic but those with knowledge of the program believe it seems legitimate, according to IGN.

Co-founder Gabe Newell has been open in the past about the company's potential to create a third installment of its popular zombie first person shooter game, the second has been a successful low-budget title for the company as well as a fan favorite for gamers. He has never directly ruled out the possibility so it's not unlikely that the company would be ready to capitalize on the franchise in the coming months.

The first game took place in an urban setting after a zombie outbreak. Four lone immune survivors must fight their way through wave after wave of zombies and make it to safe zones. The popular sequel added four new characters, the setting of New Orleans and a slew of new carnage inducing tools of destruction, including melee weapons.

These rumors are completely unconfirmed by Valve or any other party able to confirm the news. However, it does come off the news that the company had been having internal discussions about "Left 4 Dead 3," Half-Life 3," and "Source 2." This information was based on some internal information that was available to the public for a brief period of time from the company's internal bug-tracking projects.

Left 4 Dead has blossomed from a small proof of concept shooter into a full-fledged franchise. The game's downloadable content has kept its dedicated fan base alive. The game is not a traditional campaign. It uses single sustainable levels that each take about an hour to complete. The game is meant to promote four-player co-op and has given those who want to develop new skins and weapons for the game a place to put their downloads so other users can buy them. The game can be downloaded directly from Steam.