ABUJA, Nigeria (AP) — Six people accused of plotting to overthrow Nigerian President Bola Tinubu were arraigned in court on Wednesday on charges of treason and terrorism.

All six pleaded not guilty to all 13 charges, which were announced on Tuesday. The suspects have been in the custody of the secret police for months.

The six included a retired major general and a serving police inspector. A seventh suspect, former Bayelsa state Gov. Timipre Sylva, is accused of helping to conceal the plot and is still at large.

The court adjourned the case until April 27, when it will hear bail applications.

In the charge sheet, authorities said the suspects “conspired with one another to levy war against the state to overawe the president of the Federal Republic.”

The Nigerian government first said it had foiled a coup attempt in January, when it announced that several military officers would stand trial.

The coup would have ended nearly three decades of democratic rule in Africa’s most populous country, which returned to democracy in 1999.