A Thousand Oaks doctor who was arrested twice this year on suspicion of drugged driving is now accused of treating patients while under the influence of prescription painkillers, authorities said Tuesday.
Dr. Daryl Westerback was most recently arrested on June 5, when a narcotics detective believed Westerback was driving under the influence, according to a statement from the Ventura County Sheriff's Department.
The psychiatrist had previously been arrested March 8 on suspicion of driving under the influence of drugs and felony child endangerment after a traffic collision in Thousand Oaks, according to the statement.
In addition, authorities suspected the doctor had improperly written some prescriptions. at least one of Westerback's patients has died recently of a prescription painkiller overdose, said Ventura County Assistant Sheriff Gary Pentis.
"We have between 10 and 12 doctors who we feel are criminally operating within Ventura County," Pentis said.
He said Westerback roused suspicions because of his drugged-driving arrests, and because he recently changed the focus of his practice from psychiatry to pain management.
"So as we looked into it, we found that last year, a patient died of an opiate overdose under his care," Pentis said. "So we went to his office, and it appeared he had been practicing medicine while under the influence of opiates."
Prosecutors have not charged Westerback, but the task force, along with the U.S. Drug Enforcement Agency and the California Medical Board, were investigating his practice.