Attorneys for a sitting Maryland state senator indicted on bribery and obstruction-of-justice charges say the preceding FBI investigation was part of an attempt to implicate members of the Baltimore City Council and Maryland legislature.

The Baltimore Sun reported Monday that Sen. Nathaniel Oaks' public defenders said in a new court filing that the Federal Bureau of Investigation "coerced, cajoled and enticed" Oaks' acquaintances into assisting the investigation. The Baltimore Democrat is accused of taking $15,300 from an FBI source, who his lawyers say pushed the idea of payments.

The federal government said last week that Oaks confessed to taking money and tipping off the target of a federal investigation, charges Oaks is contesting.

The defense's claims could expand the federal investigation's known scope, but Oaks is still the only person known to be charged.