Different body fluids with different blood types?

One of the strange things about Russian serial killer Andrei Chikatilo is that medical testing post-arrest showed that his blood and saliva were type A while his semen was type AB. It’s stated that as far back as 1988, Russian investigators were told of cases like this.

Unless he was a chimera (not determinable, since he’s now dead), how is this possible?

Asked and answered.

Chimerism would do it. We are not entirely sure how often it happens.

I suppose a very specific mutation early in embryological development could do the same.

I remember a film about Chikatillo. I think it was The Murders Department- I’ve looked for it on IMDB and been unable to find it (it had Donald Sutherland. I’m sure of that). One of the things I remember from the film is that the initial investigator got a lot wrong. They insisted that Chikatilo had blood of one type and semen of another. Later investigators insisted that the person just screwed up.

Now that I finally have high speed net access (I’m borrowing somebody else’s with their express consent) I finally found the film. It’s Citizen X. Either the film misrepresents the issue or my memory is faulty.