Human Rights Watch says it has documented the killings of at least 18 people by a police unit in Central African Republic.
The head of the police unit, Robert Yekoua-Kette, already has been removed from the position, but human rights activists say he should be prosecuted in connection with 13 of the cases.
Human Rights Watch researcher Lewis Mudge said Monday that people in the country will not believe there can be rule of law unless Yekoua-Kette faces justice.
The killings were between April 2015 and March.
Impunity has long reigned in Central African Republic, where the president of a decade was overthrown by rebels in 2013 and sectarian violence followed.
While elections held earlier this year were peaceful, there are fears the country is again teetering on the edge.