Chicago police are investigating after video was posted online showing the shooting death of a woman who was shielding her toddler from gunfire.

Police spokesman Anthony Guglielmi released a statement Sunday night calling the video's release "unauthorized." Guglielmi adds that police have notified the Cook County State's Attorney's Office about the video and that the department is working to determine how the video was accessed. WBBM-TV reports the video came from a city surveillance camera on Chicago's West Side.

Twenty-four-year-old Brittany Hill was fatally shot on Tuesday as she stood next to some parked cars with her 1-year-old daughter in her arms. Authorities say Hill placed her body over the girl to shield her from the bullets.

Two central Illinois men have been charged in Hill's death.