A video showing a man firing at someone while streaming the incident live on social networking site Facebook's "Live Video" feature went viral and was being investigated by Chicago police, a media report said.
In the video clip, a man in a blue hat is seen talking into the camera while standing in front of a convenience store in Chicago's West Englewood neighbourhood, tech website Mashable reported.
Moments later, shots are fired and the phone drops to the street with camera facing up. The apparent assailant steps into the frame and continues the firing. Soon a woman's scream is heard, the report added.
While people raised questions on video's authenticity, Chicago Police said the video is likely legitimate.
"Chicago Police Department is aware of the video on social media in question and suspect the video is connected to the incident," a police officer was quoted as saying.
The officer said that detectives were working to confirm its authenticity, adding that a man, believed to be a known gang member, was shot at the location seen in the video.
The suspected shooter was still at large.
"Live Video" feature allows users to broadcast live video from their smartphones, making it easier for them to disseminate news faster to a large audience.
