Few dispute the surge in prescription drug abuse over the past decade.

By 2007, more teens were using painkillers than smoking pot, the Centers for Disease Control said. Addictions and overdoses spiked.

So it followed that shutting the pipelines became a priority for law enforcement. That led agents to Dr. Norman Werther.

On Tuesday, federal prosecutors in Philadelphia opened their trial against Werther, a 73-year-old Horsham doctor who, they say, turned his long-standing practice into one of the most egregious "pill mills" they had seen.

Assistant U.S. Attorney Nancy Beam Winter told jurors that drug dealers shuttled weekly caravans from North Philadelphia to Werther's office in Willow Grove, where the doctor took cash or money orders and gave the parade of "psuedo-patients" oxycodone scripts to be filled and resold - sometimes pill-by-pill - on city streets.

Between 2009 and his arrest in 2011, Werther allegedly furnished hundreds of thousands of pills to six drug networks and laundered his cash in multiple bank accounts. His once struggling physical therapy practice exploded, Winter said, and his income jumped from $50,000 to more than $1 million a year.

"Drug dealers come in all shapes and sizes," she told jurors.

A lawyer for the doctor conceded that some drugs ended up in the wrong hands, but insisted Werther was a victim of the conspiracy, not an organizer of it.

The attorney, David M. Laigaie, asserted that Werther unknowingly inherited the dealers and their patients when he bought the pain-management practice from a former Philadelphia orthopedic surgeon in 2008. The drug traffickers then coached patients what to tell the doctor to get a prescription, bribed and "co-opted" members of Werther's staff and enlisted them to create false records.

"The groups and their patients went to great lengths to deceive Dr. Werther," Laigaie said.

Dozens of others were charged in the case, but nearly all have pleaded guilty and many agreed to cooperate.

As the trial opened, the balding, bespectacled doctor shared the defense table with codefendants half his age, Angel Duprey and Troy Brinkley, each accused of running separate drug networks that bought their wares from Werther.

Duprey's lawyer, David Zellis, urged jurors to look critically at the government's case. Brinkley's attorney, Lawrence Krasner, said the evidence against his client amounts to bank records and testimony from "people who have spent their lives lying."

One key witness will be a former patient and ring member who tipped off the Drug Enforcement Administration in 2010. The woman agreed to wear secret recording devices during her visits, John Hipple, a Chester County police officer assigned to a DEA task force, told the jury.

The prosecutor acknowledged that the woman was well-paid for her work - court records show she got $193,000 for cooperating in the case - but said some of it came from a DEA award program because the witness helped agents recover millions of dollars in crime proceeds.

Winter also promised jurors they'll see the equivalent of a smoking gun - a note Werther's wife wrote to the staff in 2011 warning them to turn away patients from the dealers because agents were closing in.

And she told them they'll hear how Werther gave oxycodone to one of his patients, a onetime tennis prodigy named Nathaniel Backes, after Backes came to him seeking help to break his addiction to the drug. In September 2010, Backes died from an overdose of oxycodone and cocaine.

"When you're involved in the illegal drug market, that's what happens: Someone dies," Winter said.

If convicted of the major charges, Werther faces at least 20 years in prison and could be sent away for the rest of his life. The trial, before U.S. District Judge Berle M. Schiller, is expected to last at least three weeks.