CHICAGO (CBS) — A window shattered high above a luxury Streeterville high-rise over the weekend, sending shards of glass raining onto the street below.

As CBS 2’s Marissa Parra has learned, it’s not the first time. And the city is now demanding answers from property management.

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The building manager at 600 N. Fairbanks Ct. said this was not a story, because there was no safety concern to the people inside. She also said the windows are double-paned.

But what about the people outside – especially when we are told this has happened not once, not twice, but at least three times in the last 10 years?

Over the weekend, a carpet of glass lined the alley off Fairbanks Court and Ohio Street – directly below the missing glass pane that was seen stories up at 600 N. Fairbanks Ct.

It did not seem to raise alarm bells for anyone else, but it did for Rob Foster.

“I used to work at 232 East Ohio – that’s the brick building here on the left,” he said.

The 232 E. Ohio St. building is separated from the 600 N. Fairbanks Ct. building only by an alley. In 2013, Foster put up a Reddit post with a photo of another missing windowpane from the same Fairbanks Court building.

“The first time it was just kind of interesting – like, ‘Oh my gosh, you know, a window fell out of a building,” Foster said, “and by the second and third times, we got to the point where we were kind of not really walking under that building.”

The 600 N. Fairbanks Ct. building is undeniably sleek with a seamless façade. It was designed by the renowned architect Helmut Jahn – who died in a bicycle accident in the western suburbs just recently – and its condos boast floor-to-ceiling windows.

But Foster said he has seen those windows hit the pavement multiple times. It was even documented in reports published back in 2013.

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“The one that crashed in the front of the building, you know, concentrated over there, but it scattered far enough, you know, there that you could find was pieces of it all the way over by what at the time was a Dominick’s, but is now the Whole Foods,” he said.

The Whole Foods in question is at 233 E. Grand Ave., a whole block south.

Again, we spoke to the property manager – who said while she didn’t think there was concern for people inside, she had no comment as to the safety of people walking below.

Falling glass from buildings has proven deadly in the past. In 1999, a woman died from glass that fell from Chicago’s CNA Plaza.

So far, police said they have no reported injuries from the fallen glass outside 600 N. Fairbanks Ct. But Foster worries one day, that luck might run out.

“It’s not an abandoned alley. The hotel has a valet. In lunch hour here around here the summer, it’s very crowded,” he said. “We used to walk through that alley all that time. Rarely was the alley completely empty. There would always be a person or two going through it.”

Foster no longer works next door and he never got answers. But he hopes this time, someone will crack the case and keep the windows intact.

“Answers would be cool, yeah,” he said. “I suppose best case scenario is that there really is no safety issue, and when it did happen, it really was just some unpreventable accident. If there is a safety issue, obviously, somebody needs to do something to fix the building so it doesn’t continue to happen.”

Police who responded Saturday night told us while there were no injuries, they had been told two cars were damaged. There were still no leads late Thursday about why the glass windowpane broke over the weekend to begin with.

We also asked the Chicago Department of Buildings about the issue. They said they ordered a full top-to-bottom evaluation of all the exterior windows at 600 N. Fairbanks Ct.

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We’ll keep digging and reveal what we find.