(a) Subject to Subsection (b), in the course of investigating an alleged criminal offense, a peace officer may inquire as to the nationality or immigration status of a victim of or witness to the offense only if the officer determines that the inquiry is necessary to:
(1) investigate the offense; or
(2) provide the victim or witness with information about federal visas designed to protect individuals providing assistance to law enforcement.
(b) Subsection (a) does not prevent a peace officer from:
(1) conducting a separate investigation of any other alleged criminal offense; or
(2) inquiring as to the nationality or immigration status of a victim of or witness to a criminal offense if the officer has probable cause to believe that the victim or witness has engaged in specific conduct constituting a separate criminal offense.