Newly uncovered domain registrations suggest Quantic Dream may be working on a new PS3 game named Fiv5.
This week, Quantic Dream boss David Cage called on developers to stop making games about space marines and focus on more mature issues like families and politics.
He also told the PlayStation Blog last week: "For our next project we're going to build on what we have discovered with Heavy Rain. We own this genre of Interactive Drama and we want to show that Heavy Rain was not a coincidence; it is something that makes sense and we can build on it.
"We're going to be exploring a different direction, which will still be very dark and still for adults, but completely different to Heavy Rain. Our challenge is to satisfy our fans, and also surprise them."