"I was intoxicated, but not pissing."

DNA-Pro Bono

I was taken into custody because a cop thought I was pissing. I was intoxicated, but not pissing. They scanned my thumb with a portable device and took my photo right on the street. I am a professional, white male with no record. I was released and not charged with anything. They put me through the ringer. I didn’t even go to central booking. They held me for 5 hours. Honestly, I don’t recall, but I think I gave them a DNA swab as a bargain to get released. Do they have the right to do that if not arrested? Can they store my DNA? This is bs. I am open to any legal advice from an attorney. Thank you.