One of the men charged with killing the cousin of NBA star Dwyane Wade was "on his daily break from an electronic monitoring bracelet" at the time of the murder, Chicago police said Sunday.

An exasperated Chicago Police Superintendent Eddie T. Johnson said at a news conference that Derren Sorrells' ankle monitor wasn't active when 32-year-old Nykea Aldridge was shot and killed in front of a school on Friday. Sorrells and his brother, Darwin Sorrells Jr., were charged with first-degree murder and attempted murder on Sunday.

"When Nykea Aldridge registered her child at school on Friday afternoon she wasn’t aware that shed be the subject of national headlines just hours later," Johnson said.

Both brothers were known gang members and repeat offenders, Johnson said. Darwin had been out on parole since February and was a "career gun offender," Johnson said. Derren had six prior felony arrests. Derren's ankle monitor was inactive from 8 a.m. to 4 p.m., ostensibly so he could look for work, Chicago police Cmdr. Brendan Deenihan said on Sunday.

“This individual chose to use his time by killing someone," Deenihan said.

Police believe the Sorrells brothers intended to shoot the driver of a vehicle that ferried Aldridge to the school where she was attempting to register her child. The driver, who immediately cooperated with police, was allegedly targeted because he "exchanges looks" with the suspects and was from out of town, Deenihan said. The Sorrells tried chasing the driver down and fired at him, police said, but instead hit Aldridge, who was pushing a baby carriage.

Aldridge was hit in the head and arm. The baby was not injured.

Deenihan said investigators were able to identify the Sorrells after viewing surveillance video from the school and speaking with a school security officer.

Chicago has been in the throes of a major uptick in gun violence this year, largely centered in a few South and West Side neighborhoods, after years of seeing declines. This July alone, there were 65 homicides — the most that month since 2006.

Wade, whose charitable organization, Wade's World Foundation, does community outreach in the Chicago area, signed with the Chicago Bulls in July after 13 years with the Miami Heat. He and his mother, pastor Jolinda Wade, participated Thursday via satellite in a town hall meeting in Chicago on gun violence hosted by ESPN.

Wade has reacted to his cousin's shooting only online, tweeting Friday: "My cousin was killed today in Chicago. Another act of senseless gun violence. 4 kids lost their mom for NO REASON. Unreal. #EnoughIsEnough."

Wade also tweeted Saturday morning: "The city of Chicago is hurting. We need more help& more hands on deck. Not for me and my family but for the future of our world. The YOUTH!" adding in a following tweet, "These young kids are screaming for help!!! #EnoughIsEnough."

It is not the first time Dwyane Wade's family in Chicago has been affected by gun violence. His nephew, Darin Johnson, was shot twice in the leg in 2012 but recovered.

The Associated Press contributed to this report.