It happened last night at Rockwell and Elston in the city's Avondale neighborhood.
A federal investigator completed his on-site inspection where construction worker Gustavo Briceno was killed.
"They wanted to know how long they were out there working," said neighborhood business owner Dennis Firkus. "It was just (Wednesday) that they came out here and started."
Firkus, owner of Done Rite Auto Repair, says an OSHA investigator not only interviewed him and his employees but also looked at footage from his business' security cameras that showed what happened before Briceno was trapped in the sewer he was working in.
"They were trying to pull him out of the sewer (Wednesday) and they had these ladders, they were hooking up these ropes and all kind of stuff. It was crazy, a lot of people out here, it was just insane," said neighborhood resident Dave Mackowiak.
It was Wednesday night when emergency crews were called to the intersection of Elston and Rockwell on Chicago's Northwest Side, where a 25-year old Briceno and his partner were working inside the sewer, installing plastic lining, when the area was hit by torrential rains.
Police say the Kenny Construction worker had removed his safety harness to reach a confined space when he was swept away by the rushing water which flooded the area.
"The contractor had the camera going both ways in the sewer to see if we could find him faster," said CFD Chief Michael Fox.
Briceno's father was consoled at the scene as his son's body was found in the sewer a block away.
A spokesman for Kenny Construction, Jacque Fourchy, issued a statement Thursday afternoon that reads in part, "We are deeply saddened by the loss of one of our co-workers last night. ?Kenny Construction places the highest value on safety. We are working cooperatively with authorities on the investigation."
Briceno lived in Glendale Heights and was a father of three children. Friends describe him as a hard worker.
But Thursday his grieving wife, who first learned about the incident through social media, wonders why the company allowed crews to work in last night's storm.
"I was like, 'Oh my god I hope it's not him. I hope it's not him,' And the whole time something was telling me in my heart that it was him," Sandra Hernandez said. "Usually when it rains they're off, so I don't know why they had him working (Wednesday)."
The Chicago Water Department said that Kenney Construction has long-standing contracts with the city and has a good safety record.
OSHA continues their ongoing investigation, which they say could take the better part of six months.