According to LTV, six KNAB employees left Ušakovs' office carrying black sacks and briefcases.
There is also information from LTV about a search being carried in Ušakovs' place of residence on Bergenas street in the posh Mežaparks neighborhood, Rīga.
The Rīga City Council says it has no information about the events and on whether Ušakovs had come to work on January 30.
Meanwhile opposition councilors are collecting signatures with the goal of sacking Ušakovs from his post, opposition councilor Vilnis Ķirsis (New Unity) said.
Later on January 30, Ušakovs confirmed to the press that a search had been carried out in his home, but that no charges have been brought against him.
He praised the professional conduct of KNAB employees and said he does not intend to step down as Rīga mayor.
"I can avow that my conscience is clean," he said.
Later on January 30 KNAB announced on its website that the searches carried out that day are related to an ongoing criminal probe. Likely, but not certainly, this makes the searches related to the ongoing investigation over corruption in the Rīgas satiksme municipal transport company.
KNAB said that, as of now, no one has been arrested, and that more detailed information is to follow as soon as revealing it won't harm the investigation.
On December 11, 2018, KNAB employees searched an office at the Rīga City Council as part of a criminal probe over multi-million tenders in the Rīgas satiksme municipal company.