A Latvian court on Tuesday sentenced an engineer to six years in jail for a 2013 supermarket roof cave-in that killed 54 people in the Baltic country's worst peacetime disaster.

The Maxima store collapse in a suburb of the capital Riga injured dozens and triggered the resignation of the prime minister.

Presiding judge Erlens Ernstsons found Ivars Sergets, aged 38, "guilty of homicidal negligence due to gross errors in structural calculations, which directly led to the collapse."

The verdict was live-streamed online from the court in Riga.

Ernstsons also ordered Sergets, who had pleaded not guilty, to pay 5.7 million euros ($6.2 million) in damages to the victims' families.

Eight other defendants were acquitted.

They include architects, building project managers, a Maxima security specialist and former officials of the Riga City Construction Oversight Authority.

The Maxima store collapse injured dozens and triggered the resignation of the prime minister
The Maxima store collapse injured dozens and triggered the resignation of the prime minister AFP / ILMARS ZNOTINS

Relatives of the victims walked out of the courtroom in a silent protest over what they said was a mild sentence.

"Years of grief during the court hearings, and now only one convict with merely six years to serve in prison? For 54 lives? That's like spitting in our faces," Regina Locmele-Lunova told local media.

Judge Ernstsons also ordered a fresh investigation targeting the producers of allegedly faulty roof components after finding that prosecutors had failed to adequately investigate all aspects of the disaster.

il/mas/ach