Undercover Surveillance Specialist Bob Dinnlocker

Undercover surveillance specialist Bob Dinnlocker invented some pretext to have a cup of coffee with Leidenberg. So he'd leave his DNA how when he was drinking? When he was taking a sip from the... Leylosoliva behind. That provides a DNA. And that's being compared to DNA that was collected 27 years ago. Now, the really tricky part, get the suspected killer's DNA without breaking any of the very particular rules about evidence gathering. Can Dinnlockers save the sting? Or will Adolf, the suspected murderer, walk away?