By Jermont Terry

CHICAGO (CBS) — A death investigation turned into a potentially explosive situation in Streeterville on Wednesday, as the bomb squad found a potentially volatile substance in the man’s condo.

Police said one of the dangerous chemicals they found inside a unit in this building was identified as lead azide, a potentially explosive material. Sources tell the CBS 2 Investigators that multiple explosive devices were found. The apartment was a “mess.”

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Mayor Lori Lightfoot said she doesn’t believe the materials found were pipe bombs.

Some who live in the building said the day was filled with stress and tension as investigators combed through the building Wednesday night.

CBS 2’s Jermont Terry captured video of police leaving with the potential explosives.

Lines of police cars escorted a bomb squad trailer as it hauled away the hazardous materials found inside the building at 240 E. Illinois St.

Police were initially called to the building for a death investigation. A 31-year-old man, identified as Theodore Hilk, was found around 12:30 a.m. Wednesday.

Lightfoot said it appeared Hilk had been dead for quite a while.

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Later Wednesday, new information came about and police determined they should return to the high-rise.

The FBI, a SWAT team, and the CPD bomb unit also came to the scene late Wednesday. The CBS 2 Investigators confirmed that potentially explosive materials were found in the unit where they found Hilk’s body.

The hazardous materials response had neighbors understandably worried as authorities evacuated the floor where Hilk’s body was found, along with the floors above and below.

“We didn’t know if there was something in the vents. So we turned off the vents in our house. We opened up the windows,” said a woman who asked to remain anonymous.

She has lived in the condo building for seven years. She never thought she’d experience anything like Wednesday night.

“There was a lot of constant police communication through the building, telling us they’re conducting tests and everybody should stay put,” she said.

It was a long day filled with police activity at the high rise.

“The concern was: what was going on in that apartment really?” she said.

Now neighbors here are left with nothing but questions after police confirmed potential explosives had been found in Hilk’s unit.

“Somebody was googling them, and he seems like he had a pretty educated background. So we were more worried, what was he doing, what was he thinking?” the neighbor said.

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It’s not yet clear how Hilk died. The Medical Examiner’s office has not yet announced the results of his autopsy.