Five workers died in Stockholm Monday after the construction-site elevator they were in fell 20m to the ground.
The incident happened on a site in Sundbyberg, in the north of the city.
It is being treated as a possible crime of negligence, and an investigative team has been appointed.
Gunnar Jonasson, the senior prosecutor in charge of the investigation, said: “This is a serious incident that we are now investigating.”
Andersson Company Byggnads was the main contractor on the Ursviks Torn project. The 14-storey building will contain 177 apartments, offices and parking.
The company has issued a statement on its website, saying that the deceased worked for one of its subcontractors.
It commented: “This is an incredibly tragic accident and our thoughts go out to those affected, their families and the construction workers who were on the scene.
“Currently, we have no indications of deficiencies in our work with work environment and safety. The ongoing investigations will show whether we could have done something differently to prevent the accident.”
It added that the elevator that failed was common on Swedish construction sites. It said: “We have continuously received the documentation about the elevator that we must receive according to current regulations. As far as we know, all other routines regarding the elevator were also followed until the accident.
“We are also not aware of any indications prior to the accident of deficiencies or problems with the elevator.”
Tomas Kullberg, regional chairman of the construction trade union, told Swedish broadcaster SVT: “Several colleagues at the construction site were witnesses to the fatal elevator accident in Sundbyberg.”
He added: “It is a deplorable event and you feel very bad to experience a situation like this. You have traumatic images of this whole situation and what is happening around the workplace, so they don’t feel well.”
Speaking on the same programme, Catharina Elmsäter-Svärd, chief executive of employers’ organisation Byggföretagen, called Monday an “incredibly tragic day”.
She said: “I hear from many of our members and you really feel that this affects a lot of people. There has been a strong lump in my stomach. This shouldn’t happen.”