While looking for some thermal imaging equiptment (FLIR) I happen to run across a few articles which claim to be able to convert a standard camera into a thermal imaging photography camera.
With some additional software to do image colorization it may be interesting to try during an investigation.
Please be forewarned I HAVE NOT TRIED THIS YET so use with caution and don't try it with a new or high value camera. I may find an old camera and give it a shot. Also it MUST be a CCD camera, can not be older CMos camera. If you're not sure what yours is, look up the specs on the manufacturer website.
ehow | ehow
Article with pictures on how to convert a camera.