There seems to be at least some truth to that story, as some of Serge's oldest friends are the ones who originally brought it up. I hadn't heard the tranny bit before, though.
In a situation like this, when a possible perpetrator is trained in pharmacology, it can become a tough case to crack. Something can be administered to a victim to cause an otherwise naturally bad reaction and no one is the wiser.
Pray for Serge.