CHICAGO, Il (WFLA) — Four teenagers have been arrested and charged in the fatal shooting of a Chicago police officer on Saturday, May 6 as she was heading home from work in her uniform, according to Chicago police.

Joseph Brooks, 19, Trevell Breeland, 19, Jakwon Buchanan, 18, and a 16-year-old boy were charged with first-degree murder and armed robbery in last weekend’s killing of 24-year-old Aréanah Preston an off-duty Chicago Police officer. The 16-year-old suspect will be tried as an adult, CBS Chicago reported.

The Chicago Police Department said Officer Preston was fatally shot around 1:40 a.m. Saturday during a robbery spree.

The 16-year-old suspect allegedly bragged to a friend about the shooting. That friend went straight to the police and called the suspect again, the station reported.

“During this phone call, [the suspect] made additional admissions to the robbery and the shooting – including details that had not been released,” Assistant State’s Attorney Anne Rodgers McCord said.

The four suspects were also charged with armed robbery, burglary, motor vehicle theft, and other offenses in connection with incidents that occurred on Friday and Saturday, Chicago police said.