Two men were fatally shot in two hours by Chicago police officers in separate incidents Sunday evening. Both men, police say, were armed.

DNAinfo Chicago reports that police responded to a call of armed men in the street in the city's Lawndale neighborhood on the West Side about 7:10 p.m. When officers approached a group of men who matched the description given, one of the men ran away.

After officers gave chase, police say the man pointed a gun toward one of them and the officer opened fire, killing 19-year-old Roshad McIntosh.

In a separate incident less than two hours later in the South Side neighborhood of Auburn Gresham, two police officers on foot patrol responded to the scene of a shooting that had wounded three people, according to the Chicago Tribune.

Police say the officers saw an armed teenager standing above someone lying on the ground, and that they opened fire on him after he pointed a gun at the officers, the Tribune reports. It is believed the man was 17 or 18 years old; he has not been identified as of Monday afternoon.

Both shootings are now under investigation by the Independent Police Review Authority.

Police say a handgun was recovered from the scene of the Lawndale shooting, but community members who assembled at the scene are presenting a very different version of what happened to McIntosh on social media, with some reportedly saying McIntosh was complying with police when he was shot. About 50 people are said to have assembled for a rally near the scene of the shooting amid heavy storms early Monday afternoon.

The killings come at a time when nationwide scrutiny of police-involved shootings is high in the wake of the killing of unarmed teen Michael Brown in Ferguson, Missouri, earlier this month. Brown was laid to rest at a funeral Monday morning.

Statistics on police-involved shootings are difficult to come by -- there is no national database of police shootings, as Deadspin pointed out last week while introducing their attempt to build one.