CHICAGO (CBS/WBBM) — Chicago police said people “participating in role-playing event” were responsible for a bomb scare that cleared part of Millennium Park on Saturday night.

Three subjects were detained for questioning, police said.

The incident shut down vehicular traffic along Millennium Park and displaced pedestrians at the north end of the park, where a restaurant was cleared of diners as a precaution.

The popular tourist attraction was filled with people when police received a call at 5:30 p.m. about a suspicious package in the 200 block of East Randolph Street.  They cleared the area immediately around the mirrored sculpture known as “The Bean.”

A police representative at the scene told WBBM that the package was composed of bricks wrapped in duct tape with exposed wires. The police Bomb & Arson Squad detonated the object, CBS 2 reporters learned from a fire official at the scene.

The Chicago Fire Department called a Level 1 Hazardous Material Response, and emergency vehicles filled the area. The price for the emergency response could be staggering.

One source told CBS 2 that the incident turned out to be a hoax. Chicago Police News Affairs did not use that term, but said the threat was not real.

“Further investigation revealed the device apparently had been left behind by subjects participating in a role-playing event,” a written statement issued late Saturday said. “Three subjects are being questioned in relation to this incident.”

The news release did not elaborate about the nature of the role-playing event.

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