FREETOWN, Sierra Leone (AP) — Former President Ernest Bai Koroma has been charged with treason for his alleged involvement in a failed coup attempt in November, Sierra Leone’s government said Wednesday.

Koroma has also been charged with misprision of treason, which is the crime of concealing knowledge of treasonable acts, according to a statement from the ministry of information and civic education.

On Nov. 26, dozens of gunmen launched an attack in the West African nation’s capital of Freetown during which they broke into Sierra Leone’s key armory and into a prison where the majority of the more than 2,000 inmates were freed.

At least 18 members of the security forces were killed during the clashes. More than 50 suspects, including military officers, have been arrested so far.

The charges against Koroma were announced a day after a dozen people were charged with similar offenses in connection with the failed coup.

Although he has officially retired from politics, Koroma remains an influential figure within his political party and often hosts prominent politicians in his hometown of Makeni.

There have been political tensions in Sierra Leone since President Julius Maada Bio was reelected for a second term in a disputed vote in June. Two months after he was reelected, police said they arrested several people, including senior military officers, for allegedly planning to use protests “to undermine peace.”