Info about the Portal system.
(This is just for curiosity, now, because I don't think I'll really write the story that was going to use it. It didn't seem to work, for too many reasons.) A suspect contends that at the time of the crime he was on the beach in, say, the Bahamas and has a winter's tan to "prove it." Can the sharp eye of a suitably well-informed or well-trained PI tell a beach tan from a tanning bed tan? How about a chemical tan? Could a doctor tell? (Without getting the suspect stark naked.)