Portugese online store Worten is letting people pre-order the PS4 version right now, and when asked about the title, responded: "We have the information that Worten stores will sell the game in question."
Meanwhile Czech site Supergamer has heightened speculation even further by posting both PS4 and Xbox One versions and claiming a release date of June 13.
PS4 and Xbox One versions of GTA 5 popped up on Amazon Germany at the end of last year, but were soon taken down.
Take nothing as gospel until we hear something official from Rockstar, but the evidence is starting to mount.
- Inside the world of GTA 5