CHICAGO (CBS) — Children were caught on camera vandalizing a building for seniors in the West Pullman neighborhood, leaving them terrorized.

As CBS 2’s Jermont Terry reported Monday night, the kids appeared to be younger than 10. And the seniors were worried that the kids’ mischievous acts would lead to someone getting hurt.

Those who live in the senior building off 120th and Halsted streets are uneasy.

“They are a little fearful; a little nervous,” said property manager Arletha Patterson Smith.

Here’s why – over the weekend, three youngsters piggybacked their way into the secured building. Some women tried questioning them, but the kids pulled up their hoodies and kept walking.

“When they left out, they were like: “OK, who are you coming in here? Are you up to no good?’” Patterson Smith said.

As it turns out, up to no good they were. The youngsters were seen getting to the lobby and then making their way into another door.

They tried finding anything to steal that wasn’t secure, and they eventually grabbed something – a fire extinguisher.

Then they ran out the front door.

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“Then they came outside to spray up the side of the building – the outside of the building and the bench,” Patterson Smith said. “What’s the purpose? Why?”

Patterson Smith does not consider the incident a joke.

“It bothered me, period, that it would happen,” she said. “but to see how young these individuals were.”

The children all appear to be younger than 10 and wreaking havoc on the most vulnerable – our seniors.

“Because that could be their great grandma, or grandfather they’re coming to attack or damage where they lived,” Patterson Smith said.

Just over a week ago, a resident in the building found himself targeted at the Chicago Transit Authority bus stop at 115th and Halsted streets, when youngers sprayed him with paintballs.

“He thought that he was shot,” Patterson Smith sad, “He said it hurt… and when he went down on the ground, he hurt himself.”

Between that paintball attack, and now the video of children entering the building, many are left to wonder what could be next.

“I’m just concerned that they may come back,” Patterson Smith said.

The property manager questions where the children’s parents are, and hopes the parents will get a handle on the children before finding themselves getting arrested by police.