What happens with your law enforcement DNA test?

Factual Questions
1

  1. Say you are a witness or person of interest, but not arrested, in a criminal case and volunteer to take a DNA test.
    What happens to the test results after the test shows that you are clearly not involved in the crime? Are the test results discarded or put in a data base?

  2. Same question if you are arrested, but not tried?
    3 .Same question if you are arrested and tried, but are acquitted?

If you are tried and convicted the results definitely go into a data base.