Sunday, 3 August 2014

Who put Bella in the Wych-elm? A Bayesian analysis of a 70 year-old mystery

Our work on using Bayesian reasoning to help in legal cases features in the new series of the popular BBC Radio 4 programme Punt PI, in which comedian Steve Punt turns private investigator, examining little mysteries that perplex, amuse and beguile. Full details of what we did, with links, are here.

The full programme including my interview near the end is available on BBC iPlayer here.


  1. I heard this program on Radio 4, and was very impressed with your analysis.

    I was wondering if you had applied the same technique to other cases where there is a body of corroborating evidence rather than a single conclusive piece.

    For example the the murder of Meredith Kercher still seems to generate a lot of discussion online and would seem to be a prime example.

  2. To anonymous. We have indeed applied this to other cases (although in cases where we were involved as experts we have not been able to make much publicly available). We are currently looking at the Kercher case.
    Fro previous relevant work see, for example:
    Fenton, N. E., D. Berger, D. Lagnado, M. Neil and A. Hsu, (2014). "When ‘neutral’ evidence still has probative value (with implications from the Barry George Case)", Science and Justice, 54(4), 274-287
    If you cannot access this a pre-publication draft is here:
    Also see:
    which was published as:
    Fenton, N.E. and Neil, M. (2011), 'Avoiding Legal Fallacies in Practice Using Bayesian Networks', Australian Journal of Legal Philosophy 36, 114-151, 2011 ISSN 1440-4982

  3. Thanks very much for these links.

    I will need some time to take them in, but even just reading through the headings of the first one I can see straight away that you are addressing exactly the sorts of points that are most intensively argued over in the Meredith Kercher case.

    Regards, Sam