Laroy Battle, 19, reportedly opened fire on Jasean Francis, 17, and Charles Riley, 16, in a back ally around 5 p.m. on June 20 after they and a friend walked home from buying candy at the store -- following a brief encounter with the suspect.
"The victims commented, because, since Battle is quite tall, and they asked him how tall he was and you know, hoped to be that tall someday," Deputy Chief of Detectives Brendan Deenihan told Chicago's WLS-TV. "And unfortunately, obviously we'll never see the full growth of these poor children."
The teenagers, described as “very good kids from really excellent families,” were reportedly asked by their mothers to buy candy at the store. They didn't know Battle, but after asking about his 6-foot-3 height, he reportedly followed them out and fired nine rounds at the teenagers, police said.
Francis was shot in the back, chest and left hand, while Riley was shot in the back and left leg. Both were taken to the University of Chicago Medical Center where they were pronounced dead, according to the station. The third teenager was not struck.
"He was a kid," said Latonya Pettit, Francis' aunt. "Liked video games, snacks. That was his thing. He would walk into this hospital gift shop daily and purchase snacks."
Battle was arrested after members of the community identified surveillance video of the suspect that had been released by police, Deenihan said.
"To the community members who stepped forward with information — thank you. Detectives were able to quickly identify Battle, but it was the help we received from the community that led to his arrest," Chicago Police wrote on Twitter.
The suspect – who had three previous arrests and one previous conviction for unlawful use of a weapon – admitted that he was the person seen on camera but failed to offer a motive in the fatal shooting, according to the Chicago Sun-Times.
Riley and Francis were among 12 minors struck by gunfire during a violent Father's Day weekend that saw 104 people shot in the city, the paper reported.
Violence in Chicago last weekend also saw 13 people killed in shootings, including a 1-year-old boy and a 10-year-old girl, reports say.
Battle was charged with two counts of first-degree murder and possession of a controlled substance, according to police.
Fox News' Bradford Betz contributed to this report