John Smith has been arrested for Driving Under the Influence of Alcohol and booked into the local jail. John Smith happens to be the suspect of an open sexual battery case within a neighboring jurisdiction. You are the lead detective for the sexual battery case and call the jail, requesting a DNA swab be taken at booking. The Corrections Sergeant advises you that it is a normal procedure to swab people for DNA as they are booked but does not feel comfortable doing it now because of the nature of the investigation in which Smith is a suspect. 

Is there a way to obtain this DNA swab after speaking with the Sergeant? As the lead detective, what steps should be taken for this case ?