Bill Tattenger is the business partner of recovering alcoholic Dalton Rindell, who always resented Rindell's sobriety since he believed Rindell was more aggressive a businessmen when drinking. Even in spite of Rindell abusing his ex-wife Celina Rindell and sexually assaulting his assistant Glenna Fletcher, Tattenger made Rindell have another drink to prepare for a major business negotiation.
This horrifically backfired into Rindell picking up Dr. Audrey Hale at a bar and beating her to death with a hammer in a rage. When Rindell found out, he pounced and scuffled with Tattenger because of how much damage he caused in the past and how Tattener recklessly endangered Rindell's own sobriety he cherished and an innocent woman's life and safety.
Rindell was acquitted at the murder trial due to prosecutor Sonya Paxton's prosecutorial misconduct and drunk appearance in court. It's unknown if Tattenger was ever charged with murder facilitation. (SVU: "Hammered")