"Tonight, our union mourns the loss of another student from one of our school communities. This suffering is becoming all too familiar for many of Chicago's children and families, who are educators nurture and support every day," the union said.
"The Chicago Teachers Union sends its love to Melissa's family and the Zapata Academy community, and wish them peace and healing from this heartbreaking tragedy."
Chicago Police continue to search for the suspects in this shooting.
"We wake today to the murder of 8-year-old Melissa in Little Village. Amy and I send our sincerest condolences to this heartbroken family and shattered community," Chicago Mayor Lori Lightfoot tweeted.
Anyone with information on the shooting can call or leave a tip online. A reward of $10,000 is offered for information leading to an arrest and up to $15,000 for a conviction.
"We cannot let fear cause us to lose our humanity. Please come forward so that Melissa's family will know that there is justice for her," Lightfoot said.
Shootings in Chicago increased by 11% in 2021 compared to 2020 and 63% compared to 2019 pre-pandemic levels, according to a report by police.