KNAB chief Jekabs Straume did not name Rimšēvičs but referred to a "high official of the Latvian central bank" who was "suspected of seeking a large-scale bribe... of at least 100,000 euros."
The other person targeted in the investigation was a private individual, also not named, but believed to be businessman Māris Martinsons, who was released from custody yesterday.
Rimšēvičs remains in custody but is expected to be released later Monday after LTV reported a bond of 100,000 euros had been paid by an unknown friend of the embattled governor.
Straume also made a point of warning the press that despite lots of speculation, the investigation was not linked to ABLV bank, Norvik bank or any bank currently doing business in Latvia.
"With regard to the U.S. financial institution's information about ABLV bank and also potential legal action by Norvik bank and its owners, those have nothing to do with these matters - so I would advise caution," Straume said.
Few other details were released as, Straume emphasised, investigations continue.
Earlier, Prime Minister Māris Kučinskis and Finance Minister Dana Reizniece-Ozola both expressed the opinion that Rimšēvičs should stand down, though at the time of writing he remains in his job.
Removing a sitting central bank governor by means other than his or her own resignation is a protracted and complex affair.