By Mary Wisniewski

CHICAGO (Reuters) - Richard J. Vanecko, nephew of former Chicago mayor Richard M. Daley and grandson of the late mayor Richard J. Daley, pleaded not guilty on Monday to a charge of involuntary manslaughter in the 2004 death of a suburban Chicago man.

The case sparked controversy in the nation's third-largest city because of a long-running Chicago Sun-Times investigation into why Vanecko was not charged when he allegedly threw a punch that caused the death of David Koschman, 21.

Both the Chicago Police Department and the Cook County State's Attorney's office declined to charge Vanecko while his uncle was mayor, according to court documents.

Vanecko appeared at a hearing in the Chicago criminal courts building on Monday. The judge assigned to the case, Arthur Hill Jr, had been an assistant state's attorney under Richard M. Daley when Daley was the chief prosecutor, and lawyers from both sides have to consider whether they would like the case reassigned.

"This court believes I can be fair and impartial in this case," Hill told the attorneys on Monday.

Prosecutors and defense lawyers declined to comment after Monday's appearance.

A Cook County judge appointed former U.S. Attorney Dan Webb as a special prosecutor last April to lead a new investigation, and Vanecko was charged last week. Continued...