CHICAGO (CBS)– Federal corruption charges against Alderman Ed Burke are casting a shadow over Chicago’s mayoral race.

Cook County Board President Toni Preckwinkle is now returning a huge campaign donation from Burke and others say they’re doing the same.

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The Preckwinkle campaign was rocked by Federal accusations that Burke shook down a Burger King for a $10,000 contribution to Preckwinkle’s County Board campaign.

She says she returned the money.

“I was one of the first to give back all the Burke contributions. Now I’m returning the money for the Burke event. I’ve taken the strongest actions against him,” Preckwinkle said.

Since Burke’s charges, Susana Mendoza donated a $10,500 Burke contribution to the families of three Chicago police officers who died on duty last year.

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However, one close associate of Burke isn’t backing away.

“I’ve made no secret of my friendship with Ed Burke over the years,” Gery Chico said. “I’ve been forthright about it. Some of the other candidates may not have been. I’m hearing a lot of amnesia right now.”

Over the years, Chico has only received a $1,000 Burke contribution for a failed senate run in 2004. But Chico and his law firm have donated big bucks to Burke.

Since 2005, he’s donated $40,500 to Burke and $11,500 more to his wife, Supreme Court Justice Anne Burke. That’s $52,000 dollars in total.

“It’s important to state the facts. We are who we are. And I’ve been upfront about my relationship with Ald. Burke,” Chico said. “As for mayoral candidate Bill Daley, he never received any Ed Burke donations for either his fleeting run for governor or his current mayoral campaign.”

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However, Burke has donated tens of thousands of dollars to the Daley family’s 11th Ward operation over the years.