Earlier the Re:Baltica investigative journalism center reported that these fake news were spread by a network belonging to Niks Endziņš, a musician.
He has been put behind bars at the Rīga Central prison, the police said.
As the police were investigating Endziņš' whereabouts, the police say, he allegedly defrauded two people by claiming to sell a phone on a classifieds website and asking potential buyers to cover his fuel expenses.
A 15-year-old co-conspirator without a previous criminal record was detained as well. A minor, he was forbidden from leaving the country and handed to his parents.
Re:Baltica earlier reported that Artūrs V., a pupil of Endziņš, was involved in the upkeep of the portal alongside a colleague known as Edgars.
The police started a criminal probe after several companies and institutions complained about fake news disrupting their operations.
The websites on which these stories were posted include tv-play.lv, neticams.net, redzams.lv, redzams.net, kasjauns.net, parvisu.net, and atklats.com.
The police has shut down the websites, it said.
As reported, the police launched a criminal probe after redzams.net on July 15 published a news story that the Alfa shopping center in Rīga had collapsed, with several hundred people dead and many injured.
The story, which quickly went viral, shares gross overtones with the real-life 2013 supermarket collapse in Zolitūde neighborhood, Rīga. It was the greatest single loss of life in the country following renewal of independence, killing 54 people and seriously injuring many more.
