There is a chance there wasn’t anything incriminating. The top guys kept conversations live or intimated they wanted something done; the lowers took the planning and execution upon themselves.
Yup, i've worked long enough with senior mgmt to know that anything of interest for prosecution won't be written down, especially not on company devices. Those making the mistakes of writing things down are those actually prosecuted, the ranks and files.
"You take care of it." means "Murder him and dump the body into a building foundation."
"I don't see any problems." can mean "The ambush will happen at the scheduled time. Vinnie will clean up the bodies."
etc.
You'll also see a lot of politicians using "dog whistle" statements, that are interpreted by listeners to mean something entirely different from the stated words.
That's assuming they're wiretapped. For corporate comms, just remember that email is discoverable while video calls typically aren't even retained. Be as explicit as you want, especially if you can rope a lawyer into the call and claim it's privileged.
I'm not a lawyer, but isn't RICO meant to give a way to prosecute those who are at the top of organizations that have people committing crimes like this?