BATON ROUGE, LA. — Civil rights groups and activists sued Baton Rouge law enforcement agencies over their treatment of protesters rallying against the police shooting death of a black man, saying officers used excessive force and physically and verbally abused peaceful demonstrators.

The lawsuit, announced Wednesday by the American Civil Liberties Union of Louisiana, came hours after Cameron Sterling, the 15-year-old son of the slain man spoke publicly for the first time following the death of his father, 37-year-old Alton Sterling.

Sterling was shot to death July 5 as two white officers pinned him to the pavement outside a convenience store. The killing was captured on cellphone video and circulated widely on the internet, sparking widespread protests across the capitol city.

Authorities arrested about 200 demonstrators over a three-day period, often taking to the streets in riot gear or riding in military-style vehicles. The arrests come amid heightened tensions in the city following Sterling's death, the deadly police shooting in Minnesota and the killings of five police officers in Dallas last week.

The governor and the Baton Rouge police chief have defended the response, with the chief saying Tuesday that authorities discovered an alleged plot against police while responding to a weekend burglary at a pawn shop.

"We have been questioned repeatedly over the last several days about our show of force and why we have the tactics that we have. Well, this is the reason, because we had credible threats against the lives of law enforcement in this city," Police Chief Carl Dabadie said.


The lawsuit blames law enforcement for escalating the situation.

"Plaintiffs have engaged in this peaceful speech, association, and protest on the streets, sidewalks, and medians of Baton Rouge," the lawsuit read. "Unfortunately, this exercise of constitutional rights has been met with a military-grade assault on protestors' bodies and rights."

Alton Sterling's son spoke of the protests while addressing reporters Wednesday morning. Calling his father a good man, he urged protesters not to resort to violence.

"I feel that people in general, no matter what their race is, should come together as one united family," Cameron Sterling told reporters outside the store where his father died. The teen remained composed as he spoke, a contrast from a week ago when he broke down in sobs and had to be led away as his mother talked in front of television cameras about his father's death.

In the first few days after Sterling's death, police took a reserved approach to enforcement, keeping a low profile as hundreds gathered outside the convenience store where Sterling died.

But protests escalated during the weekend as demonstrations moved away from the store and into other parts of the city, marked by a show of force by law enforcement that included police wielding batons, carrying long guns and wearing shields.

The Justice Department opened a federal investigation into Sterling's death, but Justin Bamberg, an attorney for Cameron and his mother, Quinyetta McMillon, said the family also hopes state Attorney General Jeff Landry's office "one day" will get involved.

Landry said in a statement Monday he won't have access to details of the federal investigation until it's completed and a decision has been made on potential federal charges.