Aiga Senberga, a spokeswoman for the prosecutor's office, says Biedrins and two others are suspects. She declined to identify the other two.
Senberga said Monday that if Biedrins is found guilty he could face a fine of $70,000 or a maximum five-year prison sentence. She did not say how much Biedrins allegedly owes in taxes.
Latvian media report that the 26-year-old player has already met with prosecutors to give evidence. Biedrins joined the Warriors when he was 18.
A Warriors spokesman said Monday that the team did not have any comment.