EDITORIAL: Gathered From The Net - Theories on Who Killed Sara Lance
The scene in question can be watched below
1) Komodo - many people assume that seeing as he is appearing in the next episode that it is Komodo who killed Sara. However the description for episode 304 reads..."When Oliver learns Malcolm Merlyn (John Barrowman) is alive, he suspects Merlyn killed Sara" which suggests that even after the next episode...Oliver still doesn't know who the killer is... This also could be the reason in which Sara returns to Star(ling) City...to tell Oliver that Malcolm is indeed alive and well.
2) Ra's Al Ghul - A second, and slightly more plausible theory in my opinion is Ra's Al Ghul... this seasons big bad...although this one is still contestable... Despite Ra's thinking very highly of Sara, we know from last season that he was highly aggravated and disappointed that she had left the league, and it is quite possible that this was the final straw for Ra's himself. A fan also pointed out that the music playing at the time of her death was similar, if not the same as, the music playing when Ra's was teased in the season 3 extended trailer. Lastly, Sara's response, and one of the most important parts about this death, "What are you doing here", suggests quite a bit. "What are you doing here" suggests that this character is NOT a native of Star(ling) City, as it seems it would be a surprise that they are there.
3) Thea "Dearden" Queen/Merlyn - We all know that this season will be a big one for the ladies of the Arrowverse, with Laurel FINALLY stepping into the big role of (Black) Canary, and Thea becoming some amalgam of Cheshire and Speedy II. Many fans seem to think it is Thea who killed Sara on the rooftop that night, a claim that is "further" supported by a soundcloud clip someone created after "unfodifiying" the voice. Click here to hear the clip. This theory seems wrong for a few reasons, the first being Sara's response, "What are you doing here"...it would seem that despite Oliver has not been keeping in contact with Sara after she departed, and therefore Sara would NOT know Thea had yet to return to the city, on top of that, it wouldn't be unnatural for her to be in the city, so why ask her "what she is doing there", and lastly, to this point I think it will become apparent that despite her being trained by Malcom, Thea will return to Star(ling) City STILL not knowing the secrets of her ex-boyfriend and her brother. Next, why would Thea use a voice modifier at all? Especially if she knew she was going to kill the person...yes it does add mystery for the audience, but in terms of the show....WHY would she use a voice modifier?...she wouldn't in that situation as it would serve no purpose to her. Lastly, the sound clip above does "sound" like Thea...but first off...we don't know how much the clip has been altered, secondly, do we think the Arrow writers didn't think people could do this?....they are obviously smart people...so tossing a red herring in isn't unlike them, and finally, voice clips can be modified differently, and depending on the tone used or background/foreground noise changed it can be made to sound different.
4) Malcolm Merlyn - The final theory I have seen is that it is Malcolm Merlyn. If we discount the fact that Sara could have been in Star(ling) City to tell Oliver he was still alive, then Sara's response of "What are you doing here" could make sense seeing as she may still believe him to be dead. My only gripe with this theory is the same as Thea's, why the voice modifier?...With Ra's and Komodo it seems to fit, as they are both unknown characters, but why... again yes it does add mystery for the audience, but in terms of the show...although he did change his voice throughout season 1...so that could be a reason.
PERSONAL OPINION: Ra's....Nyssa (shocking twist).....or SOMEONE NEW