Apparently he made up some elaborate story to the Chemistry stores as to why he needed a canister of carbon monoxide. He then cycled to his caravan at Appleton Roebuck, where he asphixiated his wife using the gas. He took a large dose himself to add to the credibility of his story, which was that the gas fire in the van was to blame. He then cycled back to Chemistry and returned the cylinder to stores.
The forensic team spotted however that the amount of carbon monoxide produced by the fire could in no way explain quantity the wife had received.
Ian Smith was convicted of the crime, but due to extenuating circumstances (we don't really know what these were) received only a three year sentence; of which he served about one.
He has now remarried and works as a school teacher somewhere in the South-West. (A pupil of his recently came to Physics for an interview and returned a book Smith had borrowed before the murder).
A senior member of the Physics department said of Smith ``We didn't think he could organise a piss up in a brewery'', but the murder was apparently very well planned and in the end he did only serve one year.
A BBC television program was later made about the crime, and is available on video.