Polish officials say they have detained three people who will likely face charges over the collapse of an exhibition hall roof in southern Poland that killed 65 people.

Justice Minister Zbigniew Ziobro said Tuesday that the three suspects were employees of the company that owned the building. He said police had searched the suspects' cars and apartments.

They are expected to face charges of unintentionally causing the disaster last month.

The reason for the collapse is still unclear, but officials have said that the accumulation of heavy snow on the roof may be to blame.

Investigators are trying to determine if structural flaws or poor maintenance led to the collapse.

Some information for this report was provided by AFP, AP and Reuters.