A 19-year-old black male, who was not identified by police officials, died after being shot by an officer in Madison, Wisconsin, after an argument. The teenager, who was identified by friends and family members as Tony Robinson, was a 2014 graduate of the Sun Prairie High School, according to reports.

Following the shooting incident, protests began in the area where people started chanting “Black Lives Matter” with drums. It was not clear whether Robinson had a weapon at the time of the shooting, Chief Mike Koval said, according to the Wisconsin State Journal. Koval added that officers were called to the spot because the man was jumping into traffic. A police officer reportedly followed Robinson into an apartment, after hearing a disturbance, where he shot the teenager after being assaulted by him.

“The officer did draw his revolver and subsequently shot the subject,” Koval said, according to the Wisconsin State Journal, adding that more than one shot was fired following which the officer administered first aid to the teenager. Robinson reportedly died from his wounds in a hospital. The state’s justice department has also opened an investigation into the incident, The Associated Press reported.

The incident occurred on Williamson Street in the city’s east side, and is the third case of an officer-involved killing in Wisconsin this week, WISN ABC reported.

Mayor Paul Soglin said, according to the Wisconsin State Journal: “I expect there will be a lot of anger and frustrations, particularly from friends,” adding: “I hope as the pain eases that something constructive will come of this.”

According to a new state law adopted last April, an independent agency will also conduct an inquiry into the case.