Chicago police Supt. Garry McCarthy said Michaeil Ward, 18, confessed to being the shooter, telling police that Pendleton was not his intended target.
Two men have been charged in connection with the fatal shooting of a Chicago teen whose death has captured headlines nationwide, Chicago police announced Monday.
Michaeil Ward, 18, and Kenneth Williams, 20, were both charged with first-degree murder in the death of 15-year-old honors student Hadiya Pendleton, gunned down two weeks ago just after she performed at President Barack Obama's inauguration.
They also were each charged with two counts of attempted first-degree murder and two counts of aggravated battery and discharge of a firearm.
Pendleton's mother Cleopatra Crowley told NBC News on Monday night that she was "ecstatic" that her daughter's accused killers had been charged.
"Look at what they've done to me and my family. We put so much work into raising my daughter. We had hopes. My son no longer has a big sister. They deserve to feel something that is remotely comparable," Cowley told NBC News. "But my daughter is dead, and even if they are rotting in jail, they will still be alive."
Ward confessed to shooting Pendleton in what he told police was intended to target a rival gang in retaliation for a July shooting in which Williams had been shot, Chicago Police Supt. Garry McCarthy told reporters Monday night.
"The offenders had it all wrong," said McCarthy. "They thought the group they shot into included members of a rival gang. Instead, it was a group of upstanding and determined kids, who, like Hadiya, were repulsed by the gang lifestyle."
McCarthy credited affirmative police work, not tips, with the arrests.
On Saturday night, police apprehended Ward and Williams as they arrived at a strip club to celebrate a friend’s birthday, on the same day as Pendleton’s funeral, police said. Ward did not resist, while Williams tried unsuccessfully to flee.
Before the fatal shooting, Ward had been stopped by police in a traffic stop, according to police. He had been in the same car that was later linked to Pendleton's killing.
At the Monday night news conference, McCarthy expressed sad frustration that Pendleton's death could have been prevented if the state had mandatory minimum sentencing for gun violations. Ward, explained McCarthy, was arrested in 2011 and charged with unlawful use of a firearm. He was sentenced to two years probation.
"When we talk about mandatory minimums, we're talking about saving lives," he said.
Earlier Monday, White House aides told NBC News that First Lady Michelle Obama had invited Cowley, Hadiya Pendleton's mother, to be her guest at Tuesday night's State of the Union address.
Cowley will attend the speech after she and her husband make an appearance at Sen. Dick Durbin's Washington, D.C., hearing Tuesday on gun safety.
The first lady traveled to Chicago Saturday to attend Pendleton's funeral. She reportedly met privately with family before services began, offering encouragement and telling them to "hang on" and "stay strong."
Pendleton was killed two weeks ago in a park on her city's South Side, days after she performed at some of President Obama's recent inauguration festivities. She was shot to death blocks from her school and about a mile from the president's and first lady's Chicago home.
The White House announced Sunday President Barack Obama will visit Chicago on Friday to talk about gun violence and the economy. He reportedly sent a letter to the girl's family saying that he would work as hard as possible to "end this senseless violence."