PITTSBURGH — Some of the state’s coroners, often in less-populated, more rural counties, are thwarting efforts to gather drug overdose data needed to fight its heroin and opioid epidemic, a federal prosecutor said Wednesday.

More than 3,500 people are known to have died from drug overdoses in Pennsylvania last year, most linked to heroin or opioid painkillers, and even more are expected to die this year, U.S. Attorney David Hickton said.

He spoke at a news conference on a report by the University of Pittsburgh Institute of Politics. The institute is working with his office, which heads a working group including law enforcement, medical and drug treatment experts and families affected by addiction, to come up with strategies to prevent opioid abuse and overdoses.

The report’s top recommendation is to improve real-time data on fatal and nonfatal overdoses so law enforcement and medical officials can respond rapidly to areas experiencing a rash of overdoses.

Hickton said too many coroners and medical examiners — he didn’t name or number them — aren’t turning over timely data, and he threatened “legal action ... if we can’t get this data.”

Hickton praised Allegheny County Medical Examiner Dr. Karl Williams, whose jurisdiction includes Pittsburgh, and authorities in Washington and Westmoreland counties, the two most populous border counties, for their data-gathering.

Westmoreland County Coroner Kenneth Bacha, the assistant secretary/treasurer of the Pennsylvania State Coroners Association, said his office does everything it can to cooperate with Hickton’s efforts. But he also has a large enough staff that a deputy coroner on the midnight shift can spend time crunching the numbers Hickton and Pitt need.

He said smaller coroner’s offices can’t do what he does as a full-time coroner with several full-time staffers.