The Detroit building had a code violation and less than an hour after the inspector left, the building's roof collapsed.
Heavy concrete blocks cover the sidewalk along West Davison and 14th in Detroit.
"One customer said she was at the register when it fell," said witness Dakota Sanford. "She said she was shaken up about that."
Four people were inside the 15,000-foot shopping center known as the Davison Beauty Outlet.
The building inspector left at 1:15 a.m. and by 2 p.m. came the loud crash.
"(The inspector) didn't have time to complete his inspection report, he got a call that the building collapsed," said Eric Jones, of Detroit's building and engineering department.
The building and business owners declined comment, but city inspectors say the owners did not react to a failed inspection that uncovered a leaky roof.
"Last year we had an inspector come out and we determined that the roof was leaking," Jones said. "We issued the owner a 30-day correction notice. The owner ignored the correction notice, the inspector came back out, inspected it, issued the owner a ticket.
"The owner had a court date, he defaulted - he did not show up."
The Detroit Fire Department responded for possible search and rescue but fortunately everyone was accounted for.
"The people inside will be okay," said Jack Wiley, Detroit Fire Department senior chief. "Just three of the workers and the owner."
One media member said they "must have jumped out of their skins when that thing came down."
"I'm quite sure they did," Wiley said.
The city has tagged the building for demolition, neighbors say the loss of the mini mall that carried everything including cell phones, computers, beauty supplies and clothing will be missed.
Code violations go back to last year, city officials said.
FOX 2 asked if the building should have been allowed to remain open, but Jones said the paperwork was finished.
A demolition is scheduled to happen as early as Thursday, but it could be delayed based on how stock inside the store can be moved out beforehand.