Police in Portland, Oregon have used the polygraph in the investigation of a series of dog poisonings that occurred in a public park last year. KATU News (http://www.katu.com) reports that the sole remaining "person of interest" in the case had taken slow, deep breaths during each of two polygraph examinations and "even admitted visiting 'The Lie Behind the Lie Detector,' a Web site which teaches people how to defeat the polygraph exam."
An abridged text version of the report is available here:
http://www.katu.com/news/story.asp?ID=65309
and the full video may be viewed here:
http://easylink.playstream.com/katu/040310dog_poisoning5p.wvx
It should be noted, however, that taking slow, deep breaths is not the way to pass a polygraph examination, and the The Lie Behind the Lie Detector (http://antipolygraph.org/pubs.shtml) provides an explicit warning that such breathing is to be avoided: it is easily spotted and is generally interpreted by polygraphers as a polygraph countermeasure. The countermeasures described in TLBTLD are much harder to detect, and although polygraphers often claim that they can easily detect them, no polygraph examiner has ever demonstrated any such ability.
If anything, the fact that the "person of interest" clearly did not employ the polygraph countermeasures described in TLBTLD, and instead volunteered the fact that he had researched the polygraph, might be taken as a sign of candor.