PITTSBURGH — The pain clinic tucked into the corner of a low-slung suburban strip mall was an open secret.

Patients would travel hundreds of miles to see Dr. Andrzej Zielke, eager for what authorities described as a steady flow of prescriptions for the kinds of powerful painkillers that ushered the nation into its worst drug crisis in history.

At least one of Zielke’s patients died of an overdose, and prosecutors say others became so dependent on oxycodone and other opioids they would crowd his office, sometimes sleeping in the waiting room. Some peddled their pills near tumble-down storefronts and on blighted street corners in addiction-plagued parts of Allegheny County, where deaths by drug overdose reached record levels last year.

But Robert Cessar, a longtime federal prosecutor, was unaware of Zielke until Justice Department officials handed him a binder of data that, he said, confirmed what pill-seekers from as far away as Ohio and Virginia already knew. The doctor who offered ozone therapy and herbal pain remedies was also prescribing highly addictive narcotics to patients who didn’t need them, according to an indictment charging him with conspiracy and unlawfully distributing controlled substances.

Zielke denied he was overprescribing, telling AP he practiced alternative medicine and many of his patients stopped seeing him when he cut down on pain pills.

His indictment in October was the first by a nationwide group of federal law enforcement officials that, armed with new access to a broader array of prescription drug databases, Medicaid and Medicare figures, coroners’ records and other numbers compiled by the Justice Department, aims to stop fraudulent doctors faster than before.

The department is providing a trove of data to the Opioid Fraud and Abuse Detection Unit, which draws together authorities in 12 regions across the country, that shows which doctors are prescribing the most, how far patients will travel to see them and whether any have died within 60 days of receiving one of their prescriptions, among other information.

Authorities have been going after so-called “pill mills” for years, but the new approach brings additional federal resources to bear against the escalating epidemic. Where prosecutors would spend months or longer building a case by relying on erratic informants and only limited data, the number-crunching by analysts in Washington provides information they say lets them quickly zero in on a region’s top opioid prescribers.

“This data shines a light we’ve never had before,” Cessar said. “We don’t need to have confidential informants on the street to start a case. Now, we have someone behind a computer screen who is helping us. That has to put (doctors) on notice that we have new tools.”

And Rod Rosenstein, deputy attorney general, told AP the Justice Department will consider going after any law-breaker, even a pharmaceutical company, as it seeks to bring more cases and reduce the number of unwarranted prescriptions.

Attorney General Jeff Sessions has been in lock-step with President Donald Trump about the need to combat the drug abuse problem that claimed more than 64,000 lives in 2016, a priority that resonates with Trump’s working-class supporters who have seen the ravages of drug abuse first-hand. The president called it a public health emergency, a declaration that allows the government to redirect resources in various ways to fight opioid abuse.

But he directed no new federal money to deal with a scourge that kills nearly 100 people a day, and critics say his efforts fall short of what is needed. The Republican-controlled Congress doesn’t seem eager to put extra money toward the problem.

While the effectiveness of the Trump administration’s broader strategy remains to be seen, the Justice Department’s data-driven effort is one small area where federal prosecutors say they can have an impact.

The data analysis provides clues about who may be breaking the law that are then corroborated with old-fashioned detective work — tips from informants or undercover office visits, said Shawn A. Brokos, a supervisory special agent in the FBI’s Pittsburgh division. Investigators can also get a sense for where displaced patients will turn next.

Authorities acknowledge there are legitimate reasons for some doctors to prescribe large quantities of opioids, and high prescribing alone doesn’t necessarily trigger extra scrutiny. What raises red flags for investigators are the dentists, psychiatrists and gynecologists who are prescribing at surprisingly high rates.

The effort operates on the long-held perception that drug addiction often starts with prescriptions from doctors and leads to abuse of more dangerous black market drugs like fentanyl, which, for the first time last year, contributed to more overdose deaths than any other legal or illegal drug, surpassing pain pills and heroin.

But that focus can cause law-abiding physicians to abandon disabled patients who rely on prescriptions, for fear of being shut down, said University of Alabama addiction researcher Stefan Kertesz. Those patients will turn to harder street drugs or even kill themselves, he said.

“The professional risk for physicians is so high that the natural tendency is to get out of the business of prescription opioids at all,” he said.

Another addiction expert, Dr. Andrew Kolodny, founder of Physicians for Responsible Opioid Prescribing, said prosecutors’ emphasis on “drug-dealing doctors” is appropriate but inadequate on its own.

“It’s just not really going to have that much of an impact on an epidemic,” he said. The bigger change will come from a stronger push for prevention and treatment, he said. And, he added, “They should go after the bigger fish.... the legal narcotics distributors and wholesalers who have literally been getting away with mass manslaughter.”

Investigators said Zielke charged $250 a visit and made patients pay in cash. But Zielke said prosecutors unfairly targeted him. Instead of more prosecutions, he said, the government “should promote more alternative therapies,” he said. “And they should find out why so many people have pain.”

A second indictment by the anti-fraud unit involved a cardiologist in Elko, Nevada, accused of routinely providing patients fentanyl and other painkillers they did not need. Justice officials hope to expand the data-driven work nationwide.

Will it work? As Soo Song, who watched addiction warp communities while serving as acting U.S. attorney in western Pennyslvania, put it: “The best measure of success will be if fewer people die.”