14 DAY TRIAL // Some of the players who are taking part in the major The International DOTA 2 tournament have been given a chance to visit the offices of developers Valve and one of their images suggests that both Source engine 2 and Left 4 Dead 3 are currently in active development.
The image shows an internal tracking system which lists both the previously unrevealed projects as being worked on.
Left 4 Dead 2 was launched in 2009 and since then, Valve has continued to deliver updates for the game, while the community has created more content via the Steam Workshop.
Source 2 was previously thought to be in development in order to power Valve titles on the Xbox One, the PlayStation 4 and future PC hardware.
No sign of a new Half Life video game was spotted during the visit.
Valve did not offer any sort of official comment after Left 4 Dead 3 and Source 2 were revealed.