Sincerity Does Wonders
The evidence Anya gathered against Casper and the video of the shooters' confession could be proven as insufficient or manipulated. Nevertheless, they could send Casper behind bars if they use the maid and Ricardo's confession with audio or video of the device Ricardo bugged in the study room.
However, they will have to deal with Ricardo who is untrustworthy. It will be a waste of time and effort to deal with the two-faced man who could jump the ship any second.
Rob wanted to take a look at the study room in the Matthews mansion. If Ricardo had bugged the room with a spy camera, it would be enough to send Casper to his doomed life. Or at least, they could ruin Casper's leftover reputation by showing his fake heart attack.
The same netizens and media who were sympathizing with Casper for having to go through so much at his age will start hurling stones at Casper.