They demanded a federal investigation and the release of video footage of the shooting.
The DoJ investigation announced by Lynch came after the release of video of the police shooting of Laquan McDonald.
The public release of video footage of the shooting fanned outrage and led to weeks of protests.
The announcement came weeks after the release of video of a white police officer's killing of a black teenager.
Six months ago, protesters took to the streets after the release of video showing a white Chicago police officer shooting a black teenager named Laquan McDonald 16 times.
The police shooting of Keith Scott, a black man in Charlotte, North Carolina, similarly prompted mass protests last week and the eventual release of video of the confrontation.
Just before the fall election, Mr. Saakashvili was badly damaged by the release of video clips showing brutal abuse in a Georgian prison.
The protest followed the release of video by the animal rights website Aussie Farms, which purported to show inhumane practices at the abattoir.
During an occasionally testy exchange with reporters on Thursday, Putney was asked when the public could expect the release of video showing the fatal shooting.
Those charges were quickly followed by the release of video footage showing that shooting, which prompted intense but peaceful demonstrations in Chicago.
The Chicago officer who fatally shot Ronald Johnson III as he ran from police will not be charged, prosecutors announced on Monday before the public release of video of the shooting.
