(NewsNation) — A former maintenance worker and tenant of a partially collapsed Iowa apartment building said ongoing concerns about a crack in the building were brushed off.

Maintenance workers began expressing concerns about a crack in the back of the building in 2020, former employee Aaron Aguilar told NewsNation on Friday.

“That was kind of a notable sign that we had seen over the years,” Aguilar said.

City officials earlier this week said that Brandon Colvin, Ryan Hitchcock and Daniel Prien were unaccounted for and had a “high probability of being home at the time of the collapse.”

All three have since been listed in the National Database of Missing Persons.

“Ryan was a pretty good individual,” Aguilar said.

The building collapsed on Sunday evening. Crews rescued or escorted out 20 people.

Now, the focus has shifted to recovery efforts.

“I feel that this whole incident could have been avoided if people would have followed what employees were expressing concerns back in 2020,” Aguilar said.

Maintenance workers’ concerns about the structure had been communicated to the property manager, owners and city inspectors, Aguilar said. Ultimately, he said, he felt those concerns were pushed aside and delayed.

“It’s real,” Aguilar said. “It can happen in your own backyard. If you see something, say something, please.”

The Associated Press contributed to this report.