Authorities say a federal agent who was at a Chicago airport to search the private plane that rapper Juice WRLD and his entourage arrived in administered the opioid antidote Narcan to the performer, who briefly awoke incoherent but later died. 

Chicago police spokesman Anthony Guglielmi said Monday that the rapper, whose real name was Jarad Higgins, went into convulsions while agents were searching the group's luggage in a hanger at Midway International Airport early Sunday. 

He confirmed a Chicago Tribune report that the rapper's girlfriend told the agent Higgins had taken the opioid painkiller Percocet. 

Agents found suspected marijuana and guns in the group's luggage.

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Two security guards with Juice WRLD were arrested on misdemeanor gun charges after authorities found three guns, metal-piercing bullets and a high-capacity magazine. 

An autopsy was conducted Monday. The Chicago Tribune reported that the Cook County Medical examiner's office said additional studies are needed to determine the cause and manner of death, including “cardiac pathology, neuropathology, toxicology and histology." 

2019 Bonnaroo Music and Arts Festival - Day 3
Juice WRLD performs at the Bonnaroo Music and Arts Festival on Saturday, June 15, 2019, in Manchester, Tenn. (Photo by Amy Harris/Invision/AP)
Amy Harris/Invision/AP