An old post from Mary off the Google group that is worth having here:
If you want to find out if an inmate has a warrant out, you first must get his first and last name and birth date. The counties I have called don't generally want the CDC number, but I think it is good form to
let them know you have it (and that you are a legitimate volunteer with California Re-entry).
You call the county's (or city's) non-emergency Sheriff's office number, found easily (usually) through a Google search for "(insert county here) County Sheriff". There may even be a "Records and Warrants" department listed, but count on having to ask for that number.
You will be asked the first and last name of the inmate, and his birth date. Then you will be directed to the appropriate department. You may have to repeat yourself a few times. Sometimes you will be given sensitive information.
I was told that a few weeks to a couple of months before an inmate is about to parole, CDC will contact the county where he has a warrant and "ask what to do with him". Pretty much always, the inmate will be
put "on hold" for the outstanding warrant and will be given a court date. Then it is up to the court.
Some important numbers:
Alameda County Warrants and Records: (510) 667-3699
Oakland Warrants: (510) 238-3676
Solano County Sheriff's Office: (707) 421-7000 (they will redirect you
to Warrants and Records- they would not give me the direct number)
I hope this helps. Also, Allyson tells me that if you "run up against a wall" with law enforcement, Court Clerks can be another good lead.