Drug Enforcement Administration agents reportedly conducted surprise inspections of the medical and training staffs of visiting NFL teams on Sunday.

Drug Enforcement Administration agents conducted surprise inspections of the medical and training staffs of visiting NFL teams on Sunday, per multiple reports.

According to the reports, the inspections were "unprecedented" and were done in an attempt to determine whether the staffs "violated federal drug laws governing the handling and distribution of prescription painkillers."

• NFL Week 11 Coverage Hub | Snaps: Falcons sit atop sad NFC South

The inspections were reportedly motivated by a May 2014 lawsuit where several prominent former players claimed they were routinely illegally given dangerous painkillers by team physicians in order to stay on the field despite injuries.

A DEA spokesman told ESPN that agents were "interviewing NFL team doctors in several locations" to check for potential violations of the Controlled Substances Act. The probe also includes any other staffers who may have access to prescription medicine, but shouldn't, per the Washington Post.

The sudden and surprising nature of the investigation is not unusual for the DEA, a former prosecutor told the Post. “All of the stuff they would do is behind the scenes, where the targets wouldn’t know,” the prosecutor said.

ESPN reports that the staffs of the Tampa Bay Buccaneers and San Francisco 49ers were of particular interest to the agents, but that the agents had plans to inspect other teams on Sunday as well.

The NFL said no issues were found during the surprise investigation.

“Our teams cooperated with the DEA today and we have no information to indicate that irregularities were found,” league spokesman Brian McCarthy said in a statement.

- Molly Geary