Commerce city Councilman Robert Fierro was arrested Thursday morning by FBI agents on suspicion of conspiracy and witness tampering after he allegedly tried to conceal illegal campaign contributions from a federal grand jury conducting a political corruption probe, the U.S. Attorney's Office in Los Angeles announced.

That grand jury indicted 39-year-old Fierro and two of his relatives for the alleged hiding of illicit contributions on Tuesday. His wife and sister-in-law were also indicted in connection with the case. The latter, 45-year-old Ana Perez, was indicted on two counts of making false declarations to a grand jury. She was the treasurer of Fierro's 2005 council campaign.

Fierro was expected to make a court appearance Thursday afternoon in U.S. District Court downtown. Both women were expected to surrender to authorities Friday.

Federal investigators maintain that Fierro reimbursed Perez and other family members for contributions they made to his campaign — which is illegal — then encouraged them to cover for him when the feds came knocking, another no-no.

Fierro and his wife each could face 15 years in prison if convicted; Perez would be looking at 40 years maximum.

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