Two men have pleaded not guilty to murder and other charges tied to the shooting death of a Chicago teenage girl, who days before had performed at a Washington brunch in the run-up to President Barack Obama's inauguration.Kenneth Williams, 20, and Michael Ward, 18, have been in custody since last month, when a judge ordered that they be held without bond after their first court appearance.

On Thursday, they formally pleaded not guilty to a host of charges, the Cook County State Attorney's Office said.

The two young men are accused of killing 15-year-old Hadiya Pendleton on January 29.

Police said Ward and Williams were gang members seeking revenge against the people who had shot Williams in July, men against whom Williams had refused to press charges when police arrested them.

He and Ward thought they had spotted members of a rival gang at the park when police said Ward sneaked up on Hadiya and her friends and began shooting. Williams was the getaway driver, Police Superintendent Garry McCarthy has said.

Ward later confessed to shooting Hadiya and two others in a case of mistaken identity, according to McCarthy.

He is charged with 141 counts of murder, 10 counts of aggravated discharge of a firearm, eight counts of attempted murder, two counts of aggravated battery with a firearm and one count of mob action, according to the Cook County State Attorney's Office.

Williams, meanwhile, faces 17 counts of murder, 10 counts of aggravated discharge of a firearm, two counts of attempted murder, two counts of aggravated battery with a firearm and one count of mob action.

The Cook County State Attorney's Office did not return calls from CNN on Friday, seeking an explanation as to why the two men face so many murder charges even though only one person was killed.

The Chicago Tribune, citing interviews with legal experts and former prosecutors, said it is not uncommon in Illinois for prosecutors to press a large number of charges -- with the understanding that, as the investigation evolves, many of the charges might be dropped.

The newspaper pointed out that William Balfour at one point faced 53 murder charges in the 2008 deaths of three of actress/singer Jennifer Hudson's relatives. He was convicted last May on three counts of first-degree murder.

Whatever the rationale, Ward's lawyer Jeffrey Granich slammed the 141 murder charges against his client as "extreme." He said that, in his 20 years as a practicing lawyer, he's never seen that many murder charges related to the death of a single person.

"What the prosecutors are trying to do ..., because this is a politically charged case and a case that has gotten a lot of media attention, is to show off how seriously they are taking this case," Granich speculated. "Unfortunately, with this indictment, they show not that they are serious, but that they are being absurd."

The case helped shine attention on the high murder rate of late in Chicago. It also became intertwined with the national debate over gun violence, with Obama referring to Hadiya's life and death in his latest State of the Union address as her parents looked on.