Investigations are underway into the sudden death of Juice WRLD.

The 21-year-old rapper, real name Jarad A. Higgins, died Sunday after reportedly suffering a seizure at Chicago’s Midway airport. The cause of death is still pending.

The Cook County Medical Examiner’s Office performed an autopsy Monday and determined that additional studies are required to establish the cause and manner of death. The Medical Examiner’s Office released a statement yesterday saying, “Additional studies include cardiac pathology, neuropathology, toxicology, and histology.”

The Chicago Tribune reports Juice WRLD suffered convulsions and went into cardiac arrest as federal agents were searching his and his entourage’s luggage for guns and drugs. Sources alleged the rapper “began convulsing (and) going into a seizure.” An agent purportedly administered two doses of Narcan, an emergency treatment that reverses the effects of opioids. Juice WRLD woke up but was apparently incoherent. He was pronounced dead at a nearby hospital.

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