"I don't really have an opinion of whether Steven Avery is innocent or guilty," Spalding says in the piece. "I have more of an opinion of whether I think there's been planted evidence or not and ultimately that's all this analysis will tell us is whether or not this evidence is planted."
I am a little bit stuck in the bold part of the above sentence. Especialy the part "that's all the analysis will tell us is". Could you please tell me to which part is "is" before "whether" connected? I would understand if this part would be as follows: …all what this analysis will tell us is… But I am not able to parse the original version.