@OP: you have appealed to rationality in examining this case... then you come up with this:

"1. Negligible. No different from the prior, which is dominated by the probability that someone in whatever reference class you would have put Amanda into on January 1, 2007 would commit murder within twelve months. Something on the order of 0.001 at most. "

The FACTS include 1) the police came to "her house" and discovered a murder victim in one bedroom and 2) she was tried and convicted. You seem to have given these zero weighting in your final calculation.

And this:

"3. About as high as the other two numbers are low. 0.999 as a (probably weak) lower bound."

Did your prior of "0.001 at most" apply to Guede as well?

I offer $50 to the AK defense fund if you can produce a defensible Bayesian probabilities calculation showing how you got from your priors to your final probabilities. A condition is that you must account for the fact that most (let us say 80% for the purposes of your calculation) persons convicted of a crime in a democratic society are in fact guilty of it, and that you use generally defensible assumptions.

Should you try to do so, Less Wrong readers can decide if you have succeeded by voting on the post containing your calculation.

D. Alex