O'Neill said he did not know whether Garrett had smuggled the pills into the jail because he had become so addicted to pharmaceuticals that he "wasn't going to suffer incarceration without them" or he intended to sell the drugs to other inmates.
"I just don't know," O'Neill said. "I don't know with you, and that's what scares me."
He noted that Garrett started drug treatment in October 2006 - about four months before the Jan. 30 heroin-induced accident.
Garrett and Britt had been in drug-rehab programs off and on for the past few years, without much success, O'Neill said.