Originally posted by Turnbull:
As Michael told Tom just before leaving Tahoe, "Right now, you're the only one I can completely trust." Logically he couldn't rule out Neri and Rocco because they were his security--and security failed. But his statement, "Fredo? He's got a good heart. But he's weak and stupid--and this is life and death," did not rule out the possibility in Michael's mind that Fredo was somehow complicit in all that happened--that's implied in "weak and stupid," and later in "Tell him I know Roth misled him."
Once Fredo revealed himself as the traitor, Michael had no need to pursue other details. If he thought Rocco was complicit, Rocco would have been dead before he got back from Cuba. Instead, both Rocco and Neri embraced him when he got back. They were both in his good graces.
Michael only trusted Tom at the time of the shooting, and specifically said that anyone could have done it because "all our people are businessmen." In other words, if he suspected Rocco or Neri then he would be looking for a motive related to their getting a better deal for themselves with michael out of the way. Ironically as it turned out, the shooting was partially about business ina sense because Fredo thought there was "something in it for me....on my own."
There has been a lot of speculation that Rocco resented the fact that Neri got closer to Mike, and higher up in the family, but I never thought this was so. If Rocco was behind Neri and Tom, he would still be Michael's number three man with enormous power, and one of a very few who were "buffers."
