Latvia president calls supermarket collapse 'murder' 23 November 2013 Last updated at 17:33 The rest of the roof collapsed while recovery teams were still working inside The Latvian president has described the collapse of a supermarket in the capital Riga as "murder." Andris Berzins said many defenceless people had been killed in "our own made disaster," and called for foreign experts to investigate what happened. At least 54 people have died since part of the roof collapsed on Thursday, but it is feared the toll could rise. Late on Saturday, the last remaining section of the roof caved in, causing panic in the surrounding area. Officials have said soil from a garden being built on the roof of the shop may have caused Thursday's collapse. We cannot call it a natural accident, because nature wasn't involved End Quote Latvian President Andris Berzins Latvia has begun three days of national mourning for the deadliest disaster since the former Soviet republic gained independence in 1991. "These three days of mourning are very necessary to go from the mindset of helplessness to rethinking what each of us has done so that we can act in practical manner, because this is an event where we must clearly say that this is a large scale murder of many defenceless people and act accordingly," President Berzins told public LTV broadcaster. He said an investigation should be held at "maximum speed." And he went on to say: "While not undermining the professionalism of our builders, I believe that we should call upon international expertise which is in no way connected with our construction business. We cannot call it a natural accident, because nature wasn't involved. The evening was calm and silent with a little fog. This is our own made disaster. Latvian families hold each other and cry, as they lay flowers beside a huge pile of rubble. The remains of supermarket shelves and shop goods, such as toilet rolls, poke out from the broken stones. But alongside the sorrow, a new feeling is starting to emerge. Anger. A fierce debate has broken out about who is to blame. In a no-holds barred interview given to Latvian television, President Andris Berzins described the tragedy as the "mass murder" of innocent civilians. He said the tragedy shouldn't be called an accident because the deaths were not caused by an act of nature. And he said the criminal probe should be led by independent investigators from abroad - implying that powerful business interests in Latvia are too closely entwined with politics to ensure a fair and honest investigation. Questions surround whether safety standards were ignored when this building was constructed in 2011; or whether work on a roof garden, which was being built on top of the store, was carried out in a negligent manner. Fading hopes As rescuers searched the ruins of the Maxima supermarket late on Saturday the final section of the roof collapsed. The BBC's Damien McGuinness said it caused the neighbouring building from where he was reporting - a shopping centre - to shake violently. People in the shopping centre at the time panicked and ran out into the street amid fears it too would collapse, he said. So far there are no reports of any fatalities Rescue teams have been working round the clock at the Maxima supermarket, digging in the wreckage of the single-storey concrete and glass building to see if anyone is still trapped inside. Ten families have told the police that they believe their loved ones could be among the rubble, our correspondent says. But, 48 hours on, hopes of finding anyone else alive are fading, he adds. By late Saturday the death toll had risen from 52 to 54. Many people have been laying flowers and lighting candles in commemoration of the dead. Thirteen firefighters were among some 40 wounded, and 29 people were in hospital as of Saturday morning, the fire and rescue service said. A rooftop garden with children's playground was being built on the top of the building. There is speculation it may have been unable to support the large amount of building materials and soil that was believed to be on the roof at the time. But the inquiry will now investigate whether building regulations were broken.