lets say someone applies with an agency and is 100% truthful in regards to there drug history, they get DQ'ed. While going through the process they were finger printed.

3 months down the road you apply with another agency and do not tell them anything about applying with another agency, do they have a system they can look in to see what other agencies you have applied with?

I could be going out on a limb here, so don't quote this as gospel, but don't you think a police department background investigator could simply ask the people conducting the fingerprint check to please list all other agencies that have requested a fingerprint check on you in the past, say 36 months?  If the list comes back with the LAPD (for example) requesting a fingerprint check on you in the last year, I'd venture to say that you'd have some explaining to do.   

If you are caught in a boldfaced lie such as this, you will be shown the door, no ifs, ands, or buts.

I think your only option is to be completely honest with your background investigator about your drug use, and your past application.

Good luck to you.

Kona

What if you weren't fingerprinted?