MARCY, N.Y. (AP) — A drone flew over the grounds of an upstate New York prison after midnight and released a package containing knives, a cellphone, bandannas, hair clippers and a green leafy substance between two dormitories, officials said Wednesday.

The package was quickly recovered by staff after the drone was detected flying above the Marcy Correctional Facility at 1 a.m. Saturday. Investigators were trying to determine who was responsible, according to the state Department of Corrections and Community Supervision.

The two double-edged knives were 8 inches (20 centimeters) and there was more than a pound (about 530 grams) of the unidentified green leafy substance wrapped in clear plastic and balloons. The package also included five pieces of paper “saturated in intoxicating chemicals” and chargers and accessories for the two hair clippers, according to the department.

The drone was recovered outside the prison, which is about 180 miles (290 kilometers) northwest of New York City,

Using drones to smuggle contraband into prisons is not unheard of. Department Commissioner Daniel Martuscello called it “an evolving but imminent threat” to the state correctional system, which has experienced about a dozen other drone incidents. The commissioner used the incident to lobby for state legislation designed to address illegal drone use.

The package recovered at Marcy had wires protruding from it, prompting a response from a bomb squad to make sure it did not pose an immediate threat.