In the stairwell of some enterable apartments in GTA IV, there is some graffiti scribbled on a wall next to the staircase. The graffiti contains references to previous protagonists of the GTA Series, including Tommy, Claude, Victor, Toni, and Carl Johnson. Next to Carl's name are the letters RIP, suggesting that Carl Johnson may be dead. However, this graffiti is a chronological error, because these characters do not belong to the same universe as GTA IV. The game contradicts itself again, as multiple billboards for the in-game business Fruntalot feature CJ's likeless. Fruntalot is a parody of the urban styled shops such as FUBU, and it would make sense to advertise a successful gangster such as CJ. On the billboard, CJ is wearing a Black Trilby and Black Suit from Didier Sachs. Some fans have claimed that it is not actually CJ, but is just a coincidence. As Fruntalot's motto is Concrete Jungle, or CJ, furthers the theory that the "RIP Carl" graffiti could be referring to someone else named Carl, rather than Johnson. It could also indicate, that 3D Universe characters ended up forever.
During the mission Hood Safari, while the player approaches Grove Street, three men can be seen riding their bikes in the opposite direction. The first two men bear a strong resemblance to Carl Johnson and Big Smoke. The third biker is disputed, with fans saying he appears to be either Ryder or Sweet. This detail is a recreation of a scene from the first mission in GTA San Andreas, Big Smoke, where the protagonists escape from the Ballas using BMX bikes. This has been proven to be an Easter egg, as Ryder and Smoke are killed by CJ in GTA SA. Also, pedestrians can be heard saying "What's good, CJ?" or "Hey CJ", whilst talking on the phone. However, this could be just another person with the same initials. The player may occasionally see a pedestrian on the street that resembles CJ's default look from GTA San Andreas.