A Maryland state senator already accused of taking illegal payments is now facing more charges.

The U.S. Attorney announced a nine-count indictment Thursday against Sen. Nathaniel Oaks that includes wire fraud and Travel Act violations for allegedly accepting illegal payments to use his position to benefit an individual on business-related matters.

The Baltimore Democrat was charged with honest services wire fraud in April and pleaded not guilty. The investigation dates to 2015, when Oaks was a House member.

Prosecutors allege Oaks was paid $10,300 for writing letters on House letterhead with fraudulent details to help a confidential FBI source obtain federal grants and $5,000 to file a bond request seeking $250,000 in state funds for a project.

Oaks' attorney did not immediately return a call seeking comment.