[dragonwriter]

> I think the law says otherwise? Evidence collected illegally is (usually?) not valid.

Evidence collected by the state in violation of Constitutional protections relating to search and seizure rights of the defendant is generally (with, however, ever-widening exceptions) inadmissible in criminal trials.

Otherwise, illegally-obtained may or may not be permitted; it quite often is, though presenting it opens one up to charges relating to the illegal act involved in gathering it.