The Cook County Medical Examiner’s Office said on Monday that it could not determine Mr. Higgins’s cause of death until additional studies were administered, including cardiac pathology, neuropathology and toxicology. The police said they did not suspect foul play.

But additional details from the Chicago police department about the incident began to fill in some blanks about the sudden death of one of the most promising and commercially successful young artists in hip-hop.

Authorities said that when the plane landed at the Atlantic Aviation hangar at Midway airport, it was carrying approximately 70 pounds of marijuana in 41 vacuum-sealed bags; six bottles of liquid prescription codeine cough syrup; and three firearms, including two 9 mm pistols and a .40-caliber pistol, along with metal-piercing bullets and a high-capacity ammunition magazine.

The plane, a Gulfstream jet, had come from Van Nuys, Calif., on Saturday. None of the suitcases carrying the drugs had names or personal items attached, the authorities said, and no drug charges have been filed. “As of last night, everybody was being cooperative,” said Mr. Guglielmi, the police spokesman.

Two men identified as security guards for Mr. Higgins — Christopher Long, 36, and Henry Dean, 27 — were charged with misdemeanors for illegally possessing guns and ammunition. Mr. Long was charged with unlawful possession of a firearm, while Mr. Dean, who had a permit to carry a gun in Illinois, was charged with carrying a concealed firearm at an airport and possessing the ammunition.