The Freemasons and other secret societies do not do a pledge status the same way college level fraternities do. These societies are based more off camaraderie than a "what are you willing to do to become one" type of thinking. People often obsess over secret societies and their activities, which honestly is by design. Humans have an innate desire to uncover things. Hence, the existence of this site and every member here. We're wired to be nosy, for lack of a better term. So, he definitely had an interest in Masons and secret societies , but I definitely think this interest and the note show more of a psychological point of starting to break due to an obsession rather than what actually lead to his demise. My working theory is more closely aligned to the secondary one. I think he was helping out a client involved in Mafia/Cartel ties and things were getting a little too close to home. He may have tried backing out, delivered some news they didn't like, or simply been attacked by a rival of the client. Keep in mind he was employed by a very powerful and wealthy client who was investigated and fined for stock fraud, of which Rivera was the finance writer for. My working theory is they wanted him to take the fall as a patsy. He declined. The phone call was a warning someone was after him. He answered it, was told, said the expletive, then tried to meet them somewhere to calm the storm. Things went sideways. Now comes the hard part. We can probably rule out the ledge of the hotel because he would've had to go through a room. We can rule out the roof of the hotel due to all the locked doors(unless someone was on payroll.) So that leaves the parking garage. That's the right angle and height. His fall was believed to be the equivalent of a pencil dive in which his legs pretty much hit the floor straight. This would also explain the hole being so clean through and the clearance. Mass wouldn't matter for terminal velocity from that height because, as someone stated, feathers and bricks fall the same. I strongly believe he was pushed off the roof. However, with that being stated, I don't know why he would not have flailed his arms and struggled in the air, making his body more lateral than it would've been. Again, these are all my own theories.
Source for secret society information: I'm an active member of two.