Police stand guard as firefighters extinguish a vacant house that was set on fire during protests following a fatal officer-involved shooting Wednesday, August 19, 2015, in St. Louis. A black 18-year-old fleeing from officers serving a search warrant at a home in a crime-troubled section of St. Louis was fatally shot Wednesday by police after he pointed a gun at them, the city's police chief said. (Photo by Laurie Skrivan/St. Louis Post-Dispatch via AP Photo)

A St. Louis police officer stands guard as firefighters extinguish a fire Wednesday, August 19, 2015, after a fatal officer-involved shooting, in St. Louis. (Photo by Christian Gooden/St. Louis Post-Dispatch via AP Photo)

Rhonda Tunstall, 40, prays for peace in the middle of the street as police move in to disperse the large crowd gathered at Page and Walton, Wednesday, August 19, 2015 in St. Louis. An armed man fleeing from officers serving a search warrant at a home in a crime-troubled section of north St. Louis was shot and killed Wednesday by police after he pointed a gun at them, the police chief said. (Photo by David Carson/St. Louis Post-ispatch via AP Photo)

Area residents talk to police after a shooting incident in St. Louis, Missouri August 19, 2015. Police fatally shot a black man they say pointed a gun at them, drawing angry crowds and recalling the racial tensions sparked by the killing of an unarmed African-American teen in nearby Ferguson, Missouri, just over a year ago. (Photo by Lawrence Bryant/Reuters)

Protestors hold their hands up as police approach them on Page Ave. after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Protestors hold their hands up as police approach them on Page Ave. after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

A protestor shouts during a demonstration after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Police arrest a protester that was in the middle of the street after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

A police officer and a protester have a confrontation during an arrest after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

A woman prays in the street as police advance on Page Ave. to try to disperse a crowd that gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Smoke rises as police attempt to disperse protesters on Page Ave. after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

A policeman rubs his eyes after police attempted to disperse a crowd using what appeared to be teargas after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police put on riot gear as protesters gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police watch from an armoured car as protesters gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police line up to block the street as protesters gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police wear gas masks as they attempt to disperse a crowd that gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police monitor the crowd as protesters gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

Police arrest a man as protesters gathered after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Kenny Bahr/Reuters)

A man holds a sign during a demonstration after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

A police vehicle is seen during a demonstration after a shooting incident in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Neighborhood residents cover their faces as the St. Louis Police Department used tear gas to disperse the growing crowd due to a police shooting earlier in the day in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Neighborhood residents cover their faces as the St. Louis Police Department used tear gas to disperse the growing crowd due to a police shooting earlier in the day in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

Firefighters attempt to put out a fire at an abandoned building with the protection of St. Louis City Police in St. Louis, Missouri August 19, 2015. (Photo by Lawrence Bryant/Reuters)

A police helicopter illuminates a burning car Wednesday, August 19, 2015, after it was set ablaze following a fatal officer-involved shooting, in St. Louis. (Photo by Christian Gooden/St. Louis Post-Dispatch via AP Photo)

A lady crosses in front of the police line as they stand guard in riot gear where protesters gather on Walton Avenue and Page Boulevard on Wednesday, August 19, 2015, in St. Louis. (Photo by Laurie Skrivan/St. Louis Post-Dispatch via AP Photo)