McCarthy, who is pushing for tougher gun laws that would increase minimum sentences for gun crimes, noted that Ward was arrested in January 2011 on a gun charge but he received probation after pleading guilty to unlawful use of a weapon. If Chicago had laws like those in New York City, McCarthy said, Ward wouldn't have been on the streets.
"This has to stop. Gun offenders have to do significant jail time," said McCarthy, who rose through the ranks of New York City's police and is the former police director in Newark, N.J.
McCarthy said the arrests occurred after police figured out that the description of the car in which the shooter fled matched the description of a vehicle in which Williams had been pulled over a day before the shootings. The police superintendent noted it didn't come from a tip from the community.
"I'm sad to point out we did not get our target audience to step up," he said.
Just as the December killing of 20 children and six adults at an elementary school in Newtown, Conn., brought renewed scrutiny of the nation's gun laws, the death of the popular Chicago teen has cast Chicago's gun violence problem in a new light.
Earlier Monday, Chicago Mayor Rahm Emanuel seemed to make just that point.
"The only time when the gun issue ever gets affected is when Newtown happens," he said. "What happens in urban areas around the country too often ... gets put to the side."
He said that while it's not wrong that massacres stir such debate, what happens on the streets of Chicago and in other urban areas "gets put in a different value system."
"These are our kids," he said, his voice rising. "These are our children."
Emanuel joined McCarthy and Cook County State's Attorney Anita Alvarez at an afternoon news conference to announce they would push for tougher gun laws that would increase the minimum sentences and require offenders to serve at least 85 percent of their sentences.
They say the law now allows offenders to be released after serving no more than half their sentences and sometimes obtain their release after a matter of weeks.