Prosecutors in Mexico say a radical teachers union that has led a decade of protests had set up an illegal financial network to fund demonstrations — and line their leaders' pockets.

The Oaxaca state teachers union led a months-long total takeover of the colonial city of Oaxaca in 2006.

This weekend they continued to block roads in Oaxaca until police ousted them. And on Sunday, the attorney general's office said it had arrested the union's general secretary on charges he led an illegal kickback scheme.

The scheme operated between 2013 and 2015, at a time when the union effectively controlled the payroll of Oaxaca's teachers.

Union officials allegedly demanded a 3.5 percent cut of unionized teachers' purchases at some local businesses.

The union would deduct the purchases from members' paychecks.