Turns out that the person The Joker is torturing in the Suicide Squad Trailer is actually Harley so there goes the Jason Todd dies in SS idea
^Bottom right you can see her glasses.
Given the images. I'm going to guess in either a flash back sequence or early scene we will see how Harley went rogue with the Joker and eventually see her and Joker being chased by Batman. My guess is the Joker gets away but Harley gets caught and this leads to her being in SS.
It also kind of explains why the Joker isn't actually seen with the Suicide Squad in pretty much all of the shots (I've seen 0 shots of him with them in movie). I'm kinda thinking he's only showing up early briefly or in a flashback. Though in all fairness I've read 0 info on the film and base it all on the single trailer and a select few cast photos lol.