Robert Forbes, who was in his mid-50s, died on Saturday as a result of his injuries, according to a statement from his family.
Forbes was struck by a car while attending a protest in Bakersfield, California, on Wednesday evening. Footage on social media appears to show him bleeding in the road afterwards.
Robert Lew, who is Forbes’ nephew, has called for justice, suggesting that his uncle was deliberately targeted by the driver of the car.
Mr Lew wrote on Facebook: "I am asking you all to stand with my family and myself as we demand justice for my uncle Robert Forbes."
Bakersfield Police Department, who have not charged the white driver, said in a statement: "Several community members have posted on social media regarding their beliefs and statements that the pedestrian in this incident was struck intentionally."
“The investigation is still open and officers are still seeking additional witnesses and video evidence,” the statement added.
According to the Bakersfield Police, the driver was not travelling above the speed limit and was not under the influence of drugs or alcohol.
A fundraising page for Forbes’ family has so far received more than $43,000 (£33,950) in donations.
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