honestly as with all previews they cut clips from different parts of the episode and mesh them together to make it seem like its more of a big deal than it really is. i think laguerta just got fed up and arrested him with nothing on him but he-said/she-said. i remember when watching the trailer for this season on youtube reading the comments and 1 comment said they worked on the set of dexter and began saying outcomes of the season. his conclusions were : debra not turning him in, laguerta finding out dexter was the real bay-harbor butcher, debra killing laguerta to protect dexter, and hannah being pregnant. lets see what happens lol