Dr. Audrey Hale was an abortion doctor who worked at the Westside Women's Health Clinic.
Although she was married to Michael Hale, she met Dalton Rindell at a bar. He took her back to his apartment where they have a one-night stand. In a fit of drunken rage, Dalton bludgeons Hale to death with a hammer, blacks out, and claims to have no memory of the assault.
Although there is evidence of his guilt, his case get thrown out of court, due to ADA Sonya Paxton's inability to proceed with the trial, as she was intoxicated herself.
Relevance to Special Victims Unit story progression
The character was used as a vehicle to expose a secondary character's weakness (Paxton) and to write them out of the show for a limited amount of time.