LAS VEGAS (AP) — A 93-year-old Las Vegas doctor faces up to 30 years in prison after he was convicted of illegally writing prescriptions for oxycodone and other painkillers that ended up in the hands of drug addicts and dealers.

A federal court jury found Dr. Henri Wetselaar guilty Thursday of all 11 drug and money laundering-related counts contained in a 2011 indictment against him, his medical assistant and a local pharmacist.

Wetselaar's medical assistant, David Litwin, was convicted of eight drug counts tied to the opioid conspiracy.

U.S. District Judge Kent Dawson declared a mistrial in the case against the pharmacist, Jason Smith of Michigan, after jurors failed to return a verdict on a single count of conspiracy to distribute oxycodone. The judge scheduled a new trial for Smith to begin May 22.

Wetselaar, a pain management practitioner, was born in the Netherlands and served in World War II. His lawyers argued that his behavior reflected his age and outdated medical education, not a conspiracy to distribute painkiller pills.

He was arrested in 2011 and accused of making 31 cash deposits with the proceeds totaling $263,000 over a 46-week period from the proceeds resulting from the sale of drugs including hydrocodone, the anxiety medication Xanax and the muscle relaxant Soma. The oxycodone prescriptions cost anywhere from $100 to $400 each, prosecutors said.

Dawson ordered Wetselaar and Litwin remanded to custody until their sentencing on June 21.