Just finished a great non-fiction book by Bruce Henderson called Trace Evidence. It is a meticulously researched account of the hunt for the I-5 killer in northern California. I strongly recommend it, on a couple of levels.
The account itself is riveting, using interviews and transcripts to detail the abductions of several women and the subsequent murder investigations. Henderson makes this read like good fiction, which is always a mark of superior non-fiction.
However, the account also appealed to me as a fiction writer, in that it provides an excellent police/forensic procedural. It shows how detective-work is similar/different across jurisdictions, and how multiple jurisdictions can cloud an investigation. It also provides a fascinating picture into how forensic trace-evidence can be used to pin down a suspect (in this case, Roger Kibbe).
A good read that is also an educational one!