CHICAGO — A federal agent who was at a Chicago airport to search a private plane that rapper Juice WRLD and his entourage had arrived in administered the opioid antidote Narcan to the performer, who briefly woke up incoherent but later died, authorities said Monday.

The plane carrying the 21-year-old rapper, who was named top new artist at the 2019 Billboard Music Awards in May, and about a dozen other people landed at Midway International Airport around 2 a.m. Sunday. Federal agents and city police officers, acting on a tip that a private plane coming from Los Angeles to Midway was carrying guns and drugs, were waiting, Chicago police spokesman Anthony Guglielmi said Monday.

During a search in a private hangar, a drug-sniffing dog made a “positive alert” on luggage carts that were loaded with bags from the plane, Guglielmi said. Inside, they found multiple bags of suspected marijuana, several bottles of prescription cough syrup, three guns, metal-piercing bullets and a high-capacity ammunition magazine, he said.

The rapper, whose real name was Jarad Higgins and who was from the Chicago suburb of Homewood, went into convulsions during the search. One of the agents administered Narcan after the rapper’s girlfriend said he had been taking Percocet, an opioid painkiller, Guglielmi said, confirming a report in the Chicago Tribune. Higgins woke up but remained incoherent, the paper reported. He was rushed to Advocate Christ Medical Center in Oak Lawn, where he was pronounced dead about 3:15 a.m. Sunday.

An autopsy was completed Monday but the toxicology test results were still pending, the medical examiner’s office said. Foul play is not suspected in his death.

None of the dozen or so people on the plane admitted to carrying the drugs, but detectives were conducting a forensic analysis to determine which bags belonged to which passengers, he said, adding that two security guards who on the plane were arrested on misdemeanor gun charges.