An alleged senior leader of a predominantly Muslim rebel group that ousted the president of Central African Republic in 2013 pleaded not guilty Monday to seven counts of war crimes and crimes against humanity at the International Criminal Court.

A court spokesman said the opening of the trial of Mahamat Said marked the end of a long wait for justice for victims in the mineral-rich but impoverished Central African Republic.

The country’s people “have been already waiting a long period of time. It is almost nine years now,” to see a member of the Seleka rebel group stand trial at the global court, spokesman Fadi El Abdallah told The Associated Press.

After a court officer read out charges including torture, unlawful imprisonment and persecution, Said told a three-judge panel: “I have listened to everything and I am pleading not guilty.”

Said, 52, is accused of running a detention center in the capital, Bangui, called the Central Office for the Repression of Banditry, from April to August 2013 where he and dozens of Seleka rebels allegedly held prisoners perceived as supporters of ex-President Francois Bozize in inhumane conditions and subjected them to torture and brutal interrogations including whipping and beating them with truncheons and rifle butts.

The court’s chief prosecutor, Karim Khan, told judges that his team would prove Said’s guilt at a trial that is expected to last months. Prosecutors are expected to call 43 witnesses.

“By the end of this trial, you will be convinced that in relation to all seven counts Mr. Said will be found guilty,” Khan said.

He said that Said was “not a passive spectator” but an active participant in crimes, hunting down civilians and bringing them to the detention center “knowing exactly what he had planned for them, what a nightmare awaited them under his control and custody.”

Defense lawyers are scheduled to make an opening statement after the prosecutors have finished.

Fighting in Bangui in 2013 between the Seleka rebels, who seized power from Bozize, and a mainly Christian militia called the anti-Balaka left thousands dead and displaced hundreds of thousands more.