Sometime between the end of the war and when Fox got shot, Coruscant Guard CMO Basher got their hands on the good drugs. That was the only explanation, really. Someone (Thorn) also made the mistake of giving Fox a datapad.

"I'm not paranoid!" Haruta hisses, eyes darting everywhere. "Ace is either the best liar I've ever met, or--well, he's not, because if he was I wouldn't suspect anything, but I do, I suspect he's a spy!" The Life and Times Of Portgas D Ace, Totally A Marine Spy