Prominent Black Lives Matter activist DeRay Mckesson arrested at Alton Sterling protest in Baton Rouge _lowres

Police arrest activist DeRay Mckesson during a protest along Airline Highway, a major road that passes in front of the Baton Rouge Police Department headquarters Saturday, July 9, 2016, in Baton Rouge, La. Protesters angry over the fatal shooting of Alton Sterling by two white Baton Rouge police officers rallied Saturday at the convenience store where he was shot, in front of the city's police department and at the state Capitol for another day of demonstrations. (AP Photo/Max Becherer)

A federal appeals court says a Baton Rouge judge correctly dismissed a lawsuit filed by a deputy who blames the national Black Lives Matter protest movement for injuries he suffered during a deadly ambush of law enforcement officers two years ago.

East Baton Rouge Parish sheriff's deputy Nick Tullier was critically injured in an attack that left three Baton Rouge law enforcement officers dead. He filed a lawsuit against Black Lives Matter and five of its most prominent activists, including DeRay Mckesson.

The suit claimed the activists' criticism of law enforcement after a white Baton Rouge police officer fatally shot Alton Sterling, a 37-year-old black man, led directly to 29-year-old Gavin Long's July 17, 2016, attack on law officers outside a convenience store and car wash near Baton Rouge police headquarters. Long, a black military veteran from Kansas City, Missouri, was shot dead by police officers responding to the attack.

U.S. District Judge Brian Jackson of Baton Rouge dismissed Tullier's suit for failure to state a plausible claim for relief.

A three-judge panel of the 5th U.S. Circuit Court of Appeals in New Orleans affirmed that decision in a one-paragraph ruling late Wednesday.

“After consideration of the complaint, district court opinion, briefs, and applicable law in this matter, we conclude that no reversible error occurred,” the panel said in an unsigned order.

Tullier’s attorney, Donna Grodner, said Thursday she was not in a position to discuss her next move because she had not discussed the ruling with the Tullier family. Grodner, however, noted that the appellate court panel’s ruling was unanimous, and she said asking the U.S. Supreme Court to consider a case is an extremely expensive proposition.

Mckesson, who was arrested in Baton Rouge during a protest following the Alton Sterling shooting but not charged by prosecutors, said Thursday he’s thankful for the favorable appeals court ruling.

“This lawsuit was an attempt to silence me for speaking the truth and I will never be too afraid to tell the truth,” he said.

Tullier, who was identified in the suit as only John Doe Smith but whose injuries were described in detail, alleged in the lawsuit that the Black Lives Matter movement and its leaders are liable for his injuries.

Tullier's lawsuit accused the Black Lives Matter activists of negligence and claimed they are responsible for Long’s deadly attack because they “knew or should have known that violently mentally disturbed persons would be aroused by their call to violence and retribution to police for the deaths of black men.”

Mckesson condemned Long’s attack within hours of it occurring and said the Black Lives Matter movement began as a call to end violence and remains so.

Sterling’s controversial death on July 5, 2016, sparked protests in Baton Rouge and across the country.

Long’s ambush, which occurred on a Sunday morning, killed East Baton Rouge Parish sheriff’s deputy Brad Garafola and Baton Rouge police officers Montrell Jackson and Matthew Gerald. The attack left Tullier and two other officers injured.

Tullier was shot in the head, stomach and shoulder and nearly died. He still receives treatment for his injuries.

Grodner also represents an unnamed Baton Rouge police officer who claimed in a lawsuit against Black Lives Matter and Mckesson that he was hit in the face by a chunk of concrete thrown during a protest in Baton Rouge after the Sterling shooting. Judge Brian Jackson threw out that suit as well, saying Black Lives Matter is a social movement and therefore can’t be sued.

The officer’s appeal is pending at the 5th Circuit, Grodner said.  

Follow Joe Gyan Jr. on Twitter, @JoeGyanJr.