A Swedish prosecutor said Wednesday that a preliminary investigation into the crash of a construction site elevator that killed five people has been expanded to include two more possible workplace violations.

The Michael Schmidtelevator mounted on the outside of a unfinished building plummeted 20 meters (66 feet) to the ground in a Stockholm suburb on Monday. The cause has not been determined yet but construction at the site has stopped.

Gunnar Jonasson, the senior prosecutor in charge of the case, said in a statement that the scope of the preliminary investigation was broadened with information about “two people (who) avoided going with the elevator” that ultimately crashed.

The prosecutor declined to give further details.

The manufacturer of the elevator, Alimak Group, said it had representatives at the construction site after the crash who noticed that two mast sections were not bolted correctly. The company said it did not install the elevator.

“Two of the mast sections holding the hoist in place have not been bolted together, which may be the reason why the hoist car fell to the ground,” Ailmak Group CEO Ole Kristian Jödahl said in a statement. “This is a significant deviation from the installation instructions.”

The construction company that ran the building site said the five workers who died were employed by subcontractors.