The builders of a supermarket that collapsed in Latvia last week, killing 54 and injuring dozens, released a preliminary report Friday saying the cause was likely a design error.
The Re&Re firm said three independent civil engineers examined the project documents in depth to produce the report on the Baltic state's worst-ever peacetime disaster.
"The main causes of the roof collapse of the shopping centre (were that) crude errors were made when calculating the load on the ceiling," said the report, seen by AFP.
The initial findings seemed to support media speculation that a rooftop garden and playground had put a strain on the award-winning, two-year-old structure.
The rooftop additions were included in the original project plans, but according to the findings the building was "designed with insufficient load carrying capacity -- three times less than required".
Two other probes, by the Latvian government and the Riga city council, are ongoing while the police conduct a criminal investigation.
On Friday, officers raided Re&Re's offices, along with those of supermarket chain Maxima and others connected to the construction of the shopping centre.
Late Thursday, the Lithuanian head office of Maxima fired the boss of its Latvian subsidiary after he made controversial remarks about the November 21 disaster.
Asked by a reporter if he would follow the lead of Latvian Prime Minister Valdis Dobrovskis, who stepped down over the tragedy on Wednesday, chairman Gintaras Jasinskas said no.
"Why? Why should I resign? Only those that feel guilty should resign," the Lithuanian executive said.
The remarks provoked a diplomatic spat which led to the sacking, according to Latvian presidential press secretary Liga Krapane.
She said Latvian President Andris Berzins called his Lithuanian counterpart Dalia Grybauskaite to complain about the chairman's "inappropriate and unfeeling comments" -- and half an hour later he was sacked.
The comments set off widespread outrage, with social networks buzzing with calls for a boycott of Maxima's 140 Latvian stores.
Latvian Foreign Minister Edgars Rinkevics condemned the remarks as "shocking and arrogant" on Twitter and the ministry summoned Lithuania's ambassador to Latvia over the matter.
Maxima is also facing other headaches: it initially claimed to have been leasing the building but has now admitted to owning it, apparently via a complex system of offshore holding companies.
Its Latvian subsidiary is also among five groups -- including Re&Re and the Riga city council -- to be hit by a first vicitim compensation claim filed on Thursday, for 100 million lats (142 million euros, $193 million).
Berzins is due to begin talks next week towards forming a new government coalition following Dombrovskis's resignation.