|Pathology||Double statutory rapist|
|Family|| Unnamed wife|
Originally from Rhode Island, Tanner was a happily married father until he traveled to New York City for a medical conference. While there, he decided to hire a prostitute, and in this way he met fifteen-year-old Lisa Downey, though he did not know she was underage.
Following that night, Tanner became obsessed with Downey, and ended up quitting his practice and his marriage, and moving to NYC. He found work at an HIV/AIDS clinic and took bribes from porn producer Max Long to conceal the HIV status of several of Long's actors and actresses, including Downey, who was working under the pseudonym of "Trudi Strutts". Sensing Tanner's obsession with Lisa, Long videotaped the doctor having sex with Downey and her friend Angela Agnelli and used the videotape as blackmail to keep Tanner from trying to pull Downey out of the business.
When Downey was murdered, the Special Victims Unit discovered Tanner's affair with her, and he was briefly a suspect. This led to him being attacked by Mr. Downey and although he escaped from that altercation, he was later shot by Angela, who had learned about the videotape's existence and sought to keep it from ending up in the hands of the police. (SVU: "Hooked")