CHULA VISTA, Calif. -- A special prosecutor is looking into complaints against Chula Vista City Councilman Steve Castaneda, 10News reported.

The 10News I-Team discovered Castaneda had not filed federal taxes since 2006 and that there is a tax lien against him for more than $49,000.

When asked about the taxes, Castaneda said, "Pay my taxes? Yeah. What are you talking about? Yes, I'm paying my taxes."

Castaneda later admitted the tax problem, but would not talk to 10News about 83 citizen complaints against him, one of which claimed he cheated to get elected.

A special prosecutor is now investigating to see if there is probable cause to charge Castaneda, which could impact his effort to be Chula Vista's next mayor. His campaign has already been endorsed by the San Diego and Imperial Counties Labor Council, an endorsement that said:

"Castaneda ... has been a consensus builder around the redevelopment plans for the Chula Vista bayfront while also fighting to protect city services in light of devastating budget cuts."

Political science expert Carl Luna said sometimes endorsements are made too early.

"Something pops up and you weren't sure about it, now you look bad," said Luna.

However, the Labor Council is standing by Castaneda. A representative told 10News by phone: "The 10News story shouldn't have an impact on our opinion or anyone else's opinion of Steve Castaneda."

When asked if an investigation by a special prosecutor would change their mind, the Labor Council representative pointed out the complaints can be filed by anyone and that nothing will come of the investigation. But if something does, some political observers said it won't be hard to backpedal out of the endorsement.

"You just say we thought this candidate was the best thing since sliced bread and we discovered it's kind of moldy around the edges, and you pick somebody else," said Luna.

10News spoke with Castaneda by phone Tuesday, but he declined to comment once again.

If elected mayor, Castaneda would administer a budget of $130 million.