The US Supreme Court on Monday vacated the decision by the US Court of Appeals for the Fifth Circuit in Mckesson v. Doe, a case arising out of the Black Lives Matter movement.

The case stems from a demonstration to protest the death of Alton Sterling, a Black man who was shot at close range by two police officers in Baton Rouge, Louisiana in mid-2016. Protesters occupied the highway in front of the police headquarters. As police began making arrests to clear the road, “an unknown individual threw a piece of concrete or a similar rock-like object,” striking an anonymous police officer who sustained head injuries.

The unnamed police officer sued civil rights activist DeRay Mckesson, who organized the protest and allegedly directed protesters to occupy the highway. While the police officer acknowledges that Mckesson himself did not throw the object, the officer seeks damages “on the theory that [Mckesson] negligently staged the protest in a manner that caused the assault.”

The district court originally dismissed the suit, holding it as barred by the First Amendment. However, a divided panel of the Fifth Circuit allowed the suit to proceed, reasoning that “a jury could plausibly find that Mckesson breached his duty not to negligently precipitate the crime of a third party because a violent confrontation with a police officer was a foreseeable effect of negligently directing a protect on the highway.”

Mckesson appealed to the Court and asserted that “his role in leading the protest onto the highway, even if negligent and punishable as a misdemeanor, cannot make him personally liable for the violent act of an individual whose only association with him was attendance at the protest.”

“We think that the Fifth Circuit’s interpretation of the state law is too uncertain a premise on which to address the question presented,” said the Court in its unsigned opinion. “Under the unusual circumstances we confront here, we conclude that the Fifth Circuit should not have ventured into so uncertain an area of tort law—one laden with value judgments and fraught with implications for First Amendment rights—without first seeking guidance on potentially controlling Louisana law from the Louisana Supreme Court.”

In addition to invalidating the Fifth Circuit’s opinion, the Court remanded the case back with instructions to consult the Louisana Supreme Court.

Justice Amy Coney Barrett, who joined the bench just last week, did not participate in the case. Justice Clarance Thomas dissented from the Court’s per curium decision, but did not provide a written explanation indicating his rationale for dissent.