I don't think Jonah was involved in the murder, but I suspect he knew about it earlier than Adam's weird TEXT message informing him of Rebecca's death (who DOES that? :scared
.
And I definitely suspect Jonah's reputation, his company's future, his network of professional contacts (attorneys, doctors, publicists, etc.), and his $$$$$$$$ played a role in all that transpired in the minutes, hours, days, weeks, and months after he was made aware of Rebecca's fate. "All that transpired" being getting the case closed STAT as a suicide and off the radar, with all persons of possible interest cleared (no matter what it took - or what needed to be avoided - to clear them).
The reason I believe this is because of the deliberately and fantastically sloppy "investigation" of a suspicious death - one that occurred in a relatively cosmopolitan place like Coronado/San Diego. Not buying it. I have no other choice but to believe much power and money was brought to bear to turn this into a fast "suicide," case closed, crime scene quickly renovated and "sold."