494 JOURNAL OF LAW AND POLICY
IV. CONCLUSION
Ultimately, the theoretical importance of the distinction
between population level distinctiveness and pairwise or small
group distinctiveness is crucial to the success of this approach
and to the statistical method employed. While this limits the
opinions of the expert to considerations of consistency and
distinctiveness, given the richness of linguistic variation, such a
limitation is appropriate to forensic authorship analysis and
provides an expert with more certain and more credible evidence
to offer the courts.
On November 2, 2009, Christopher Birks was due to be
tried. On the morning before trial, he changed his pleas to
“guilty” of the murder of his wife, “guilty” of arson, and
“guilty” of the endangerment of his children and of the
firefighters. He was subsequently handed down a life sentence
with a minimum term of incarceration of nineteen years.^53
(^53) Man Jailed over Wife Fire Murder, BBC NEWS (Dec. 11, 2009, 7:28
PM), http://news.bbc.co.uk/2/hi/uk_news/england/staffordshire/8408020.stm.