Shisui aka Tobi helped Itachi..
They say, "never say never". So I'm not gonna say that Tobi=Shisui could never be true but I am gonna say that, that statement is highly unlikely for this simple reason:
-> I believe that Shisui died before that Massacre took place.
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is where the Konaha police expresses their belief that Shisui committed suicide by drowning in the Nakano river on the night both Itachi and Shisui were absent from the
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. Now I have to concede that the police does not directly say that Shisui's body was found. But... nor do they say his body wasn't found either. Plus they never said that Shisui was
missing either. They specifically said that he
drowned. They even knew where he drowned. Thats some very specific information there.
How did the police even know that Shisui drowned if there was no body? The only other piece of evidence was
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and that made no mention of how Shisui died. The only way that the police could have known that Shisui drowned in the Nakano River is if they found his corps in
that river.
Also, during the same incident, Fugaku asked Itachi why he didn't attend the meeting the night Shisui died. And he replied
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.
We all know that:
-> the Mangekyou Sharingan was the height of Itachi's capacity
-> he was most probably the
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person to have seen Shisui.
-> We also know that you need to kill your best friend to activate MS.
-> Itachi was so close to Shisui that he considered Shisui a
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.
->
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before the massacre and after Shisui's "suicide".
All of this indicates that Itachi obtained his MS
by helping Shisui die on the night of the Uchiha meeting.