https://www.bostonglobe.com/metro/2013/06/27/former-patriots-player-aaron-hernandez-probed-two-more-murders-law-enforcement-officials-say/6PSjR68RBpguwcxmlXe2oM/story.html
Speculation, but in this article they are saying that Odin may have had knowledge about this double murder and Hernandez was worried he was going to start talking.
Makes sense. I would assume it would be something like that, sleeping with his wife/gf, or stealing money from him.