User blog comment:Ktrfgfg/Chapter 53 Predictions + Volume12Special/@comment-24294971-20131224201110/@comment-121.209.177.34-20140105063815

^^^ I agree with him. Since Marco's body was found it's a high chance that he was murdered coz a Titan would've just ate him (except for some abnormal titans).

Maybe Marco had something to do with the Titan shifters and he was gonna fo something that will reveal their secret and so Annie might've murdered him coz of that