WHEAT RIDGE, Colo. (CBS4) – Police are investigating after someone tossed a suspicious device inside the lobby of a senior center in Wheat Ridge which forced approximately 80 people to be evacuated.

The incident occurred Friday morning at the Seniors Resource Center on Chase Street. Authorities say someone threw a suspicious box that had wires coming out of it, and appeared to be an explosive, through the doors and inside the entrance.

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“We’re hoping it’s just a prank but better safe than sorry,” said Seniors’ Resource Center spokesman Felix Ortiz.

An employee says she heard a loud pop and started smelling smoke.

Somewhere between 30 to 40 clients and 30 to 40 staff members were evacuated from the center after the pop around 11:30 a.m.

Jefferson County Bomb Squad technicians brought in an X-ray device to get a better look at the contents of the suspicious box. They say it appears to have been some sort of a firework inside the box that went off. It’s unclear whether the box was dropped off as a prank or in an effort to harm those inside.

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The scene on Friday (credit: CBS)

The scene on Friday (credit: CBS)

“We’re as perplexed as you all are. I mean, this is where your grandma and your grandpa are at, where your parents come,” said Ortiz.

Police say they have gotten reports recently of some people who were unhappy with the center and say it appears to be intentional.

“It was definitely a malicious act, this was definitely a criminal act, and will be fully investigated by the police and the fire department who will assist us with an arson investigation,” Cmdr. Wade Hammond with the Wheat Ridge Police Department said.

Clients were escorted back to the center just after 4 p.m. The clients, along with staff, were shaken up but luckily no one was hurt.

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Detectives plan to examine surveillance video in hopes of catching the person who planted the device.