"We've arrested the man who was the ringleader in the plot to overthrow DRC president. He was arrested in Cape Town on Friday and we are making arrangements for him to be moved to Pretoria where he will be charged with the same charges the other 19 men are facing," said Captain Paul Ramoloko.
On Friday, police said they were still searching for two men who were part of a group accused of plotting to overthrow Kabila.
A group of 19 alleged rebels from the DRC, which included a United States citizen, appeared in the Pretoria Regional Court on Thursday to face charges under the Foreign Military Assistance Act.
The group was arrested in South Africa's northern Limpopo province on suspicion of running an illegal military operation after an investigation by a crime intelligence unit.
A separate law enforcement official said they were members of the M23 rebels that carved out a fiefdom in eastern DRC's North Kivu province, dragging the region back into war and displacing an estimated half a million people.
The M23 rebels, a group of army mutineers who launched their offensive after accusing DRC President Joseph Kabila of reneging on the terms of a March 2009 peace agreement, have since broadened their goals to include removal of Kabila and "liberation" of the country.
The men were not asked to enter pleas and were ordered to return to court on February 14.
The DRC was recently attacked by militants thought to have the backing of neighbouring Rwanda.
The DRC's mineral-rich east has been unstable and often engulfed by fighting since a 1994 genocide in Rwanda.
The ring leader would appear in the Pretoria Regional Court next week. – Sapa