An FBI agent in Kentucky died Tuesday after suffering a heart attack while jogging with another agent, according to The Herald-Ledger.
Agent Timothy S. Briggs, 46, collapsed near the FBI office in London.
The Officer Down Memorial Page has reported that Briggs was participating in the agency's physical fitness program.
The agent with him, along with EMS personnel that responded to the scene, performed CPR on him but were unsuccessful.
The Laurel County coroner said Briggs may have had a heart abnormality.
"He had a tenacity about him that not a lot of investigators have," Greg Cox, supervisory special agent in the London office, told the newspaper.
Briggs gained attention for heading an investigation into public corruption in Clay County that led to the conviction of more than 60 people on drug, vote-fraud and corruption charges.
"He made a difference in his life with what he did," head of the Appalachia High Intensity Drug Trafficking Area Frank Rapier said.
He also was on the FBI's SWAT team and the evidence-response team and is survived by his wife and three young children.