The chargesheet was submitted to Ukhia's Senior Judicial Magistrate's Court at the end of an eight-and-a-half-month investigation on Monday, according to Cox's Bazar's Additional Superintendent of Police Rafiqul Islam.
All of the accused are members of the Rohingya community.
Mohib Ullah was shot dead by a group of assailants at his office in the Kutupalong camp in Ukhia on Sept 29, 2021.
Known as Master Mohib Ullah, the 48-year-old was one of the most prominent advocates for the persecuted Rohingya Muslim minority.
Prior to his death, he had been serving as the chairman of the Arakan Rohingya Society for Peace and Human Rights. The group was founded in 2017 to document atrocities against Rohingya in their native Myanmar and give them a voice in international talks about their future.
He had also represented the Rohingya community at the United Nations Human Rights Council in 2019.
Mohib Ullah's family moved to Canada in April amid growing concerns about their safety in the refugee settlement.