A cyber-security firm apparently monitored civil rights activists during the protests and rioting that broke out in Baltimore after the death of Freddie Gray and identified several of them as “threat actors”.
Reports said a Maryland-based firm, ZeroFox, which previously watched protesters for the New York Police Department, monitored the social media output of a number of members of the Black Lives Matter movement and claimed their presence warranted an “immediate response”.
It is not clear whether the company monitored the activists as part of a formal arrangement with the Baltimore Police, though earlier this year it was in correspondence with the city’s mayor about its possible “surveillance help”.
Both the company and the city’s police department did not immediately respond to inquiries.
The details of the apparent surveillance were contained within emails first obtained by the City Explainer community news site and the Baltimore Sun. They also revealed that as Baltimore was rocked by the protests held in the aftermath of Mr Gray’s death, the city’s website was knocked out by hackers.
On Monday, Mother Jones reported that ZeroFox was involved in the monitoring of 62 so-called threat actors and 187 “threat influencers”. These included a Twitter user who was described as a main local protest organiser”.
Among those apparently monitored were DeRay McKesson and Johnetta Elzie, two prominent Black Lives Matter activists. A report by ZeroFox said it was engaged in “continuous monitoring” of their social media accounts and their geographical locations.
The report does not suggest that the pair were suspected of criminal activity but were “main coordinators of the protests”.
Mr McKesson told the magazine’s website they were not surprised that they were being watched.
“It confirms that us telling the truth about police violence is seen as a threat,” said Mr McKesson.
Mr Gray, 25, died in April, ten days he was bundled into a police vehicle by officers who had detained him. Six officers have since been charged, one of them with murder.
His death sparked many days of peaceful protests, a several days of sporadic riots that broke out in parts of the city.
A report by the coroner found that the young man died from a "high-energy injury”, most likely caused when the police van suddenly braked.