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 lower court judge was wrong to throw out a lawsuit against a Black Lives Matter organizer on First Amendment grounds.

The 5th U.S. Circuit Court of Appeals had said in April that a Baton Rouge police officer injured while attempting to arrest protesters after the 2016 killing of Alton Sterling could sue organizer DeRay Mckesson of Baltimore on the grounds Mckesson acted negligently by urging people to block Airline Highway outside the city's police headquarters. The appeals court revisited the case Thursday.

Initially, U.S. District Judge Brian Jackson had dismissed all of the officer's lawsuit, citing Mckesson's First Amendment rights and noting the Black Lives Matter group was too loosely organized to sue. The 5th Circuit's April ruling reinstated the lawsuit, saying the policeman, identified only as John Doe, could claim negligence.

After reviewing its April decision at Mckesson's request, the 5th Circuit said Thursday that Doe's complaint shouldn't have been dismissed on First Amendment grounds, even if Doe was injured during a political protest.

"We perceive no Constitutional issue with Mckesson being held liable for injuries caused by a combination of his own ... conduct and the violent actions of another that were foreseeable as a result of that ... conduct," Judge E. Grady Jolly wrote for the court as it sent the case back to Jackson.