User blog comment:Llama919/Possible Beast Titan Identity?/@comment-5774380-20150618200119/@comment-26509561-20150618213508

You never know, however I agree about the status of fan theories, but when it comes to attack on Titan you never know what is or isn't possible, also they never did find the corpse and the word "apparently" does claim that his death was never 100% legitimate, since the military police weren't being very clear. Maybe they found out that he knew something other than just exploiting forbidden and illegal history, maybe he knew more about the Titans than the military was hiding.

Presumably he was imprisoned, and pronounced dead to turn everyone's head the other way. And managed to escape the walls, or sent outside in a maze runner styled execution.