Chicago (CNN) -- The teenager who police say shot and killed Chicago honor student Hadiya Pendleton was on probation for unlawful use of a firearm, Police Superintendent Garry McCarthy said Monday night.
Michael Ward, 18, and Kenneth Williams, 20, were each charged with one count of murder and two counts of attempted murder, McCarthy told reporters. They were also charged with two counts of aggravated battery with a firearm.
They will make their first appearance in court on Tuesday morning.
Ward confessed to shooting Hadiya and two others in late January in a case of mistaken identity, McCarthy said.
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, the superintendent said.
McCarthy said Ward was sentenced to two years' probation in January 2012 for unlawful use of a firearm.
"This has to stop. Gun offenders have to do significant jail time," McCarthy said. "Criminals have to be held accountable. And there has to be a certainty of punishment when we arrest somebody with an illegal firearm."
The charges come 12 days after Hadiya was shot to death at a park in what her godfather, Damon Stuart, described as an "ideal community" on Chicago's South Side.
Police said that there were no substantive tips as to the shooter's identity, but once they had a description of the car, they linked it to a traffic stop that occurred several days before the killing.
That description and interviews with parolees led them to Ward and Williams.
McCarthy said Ward surrendered on Saturday night without a struggle, but Williams tried to escape. No weapon was recovered, he said.
Hadiya's was killed a week after she performed at one of the events surrounding Obama's second inauguration.
Shatira Wilks, one of Hadiya's cousins, said the family was elated that the suspects were in jail.
"However there is no level of comfort -- not long-term comfort -- and we are still miserable," she told CNN's Anderson Cooper. "(Hadiya) is the face of every parent's dream child. Hadiya had so many different things awaiting her in life. She was a wonderful, wonderful kid. My little cousin really was an angel."
She said Hadiya was hanging out with a volleyball team -- a group of girls and one boy -- when she was killed.
The killing -- which occurred in the city's Hyde Park neighborhood near the Obamas' Chicago home -- drew the first couple's attention.
First lady Michelle Obama attended Hadiya's funeral Saturday, and her husband wrote a note to Hadiya's family that was printed on the funeral program: "We know that no words from us can soothe the pain, but rest assured that we are praying for you, and that we will continue to work as hard as we can to end this senseless violence."
Hadiya's parents are in Washington to attend the State of the Union address, McCarthy said.
Hadiya, who often urged friends to stay away from gangs, was an honor student and band majorette at King College Prep School.
Her slaying -- the 42nd in the city this year -- also highlighted the problem of gun violence in Chicago. More than 500 people were fatally shot in 2012.
McCarthy reiterated his call for minimum sentences for gun crimes and mandatory background checks.
"Michael Ward would not have been on the street of New York City to commit this act," the impassioned superintendent said. "This is not about gun control. This is about the criminal justice system being designed to prevent gun violence."
Huge gaps in that system must be closed, he said, mentioning sentencing guidelines and universal background checks for gun buyers.
"But in my book, one of the bigger things is (a) requirement to report the loss, theft or transfer of firearms," he said.
He hoped Hadiya's case would be a turning point in the gun laws debate, and he apologized for his rant.
"I get a little emotional," he said. "Because it's true."