>>>>Can a person be forced to give a DNA sample during a traffic stop to be used in the investigation of a crime not related to the traffic stop itself?
Assuming this is a hypothetical and not based on any "real case", as always, you'd have to do some legal research. But, if I had those facts, I'd run a supression motion! And, I'd bet the farm based on an educated guess that the evidence would be suppressed. But, again, that's after giving this about 5 seconds of thought . . . .