Dr. Dennis Barkley was the director of the Lux Residential Treatment Center, a rehab clinic where he ran a scheme to overcharge both his patients and the insurance companies funding them. He colluded with Altwood Sober House, run by Anthony Parker, where Parker rapes the patients in exchange for giving them drugs, before he sends them back to Lux to repeat the cycle all over again.
Barkley was arrested and facing RICO charges. But after he made bail, he was killed with a fentanyl overdose by a social worker he conned in his clinic, Rosemary Taylor. (SVU: "Unintended Consequences")