She was expelled from Pena Nieto's Institutional Revolutionary Party in 2006 for supporting other parties' candidates and the formation of her own New Alliance party.
Gordillo's arrest recalled the 1989 arrest of another once-feared union boss, Joaquin Hernandez Galicia, known as "La Quina." The longtime head of Mexico's powerful oil workers union, Hernandez Galicia was arrested during the first months of the new administration of then-President Carlos Salinas.
In 1988, he criticized Salinas' presidential candidacy and threatened an oil workers' strike if Salinas privatized any part of the government oil monopoly, Petroleos Mexicanos, or Pemex. On Jan. 10, 1989, — about a month after Salinas took office — soldiers used a bazooka to blow down the door of Hernandez' home in the Gulf Coast city of Ciudad Madero.
Like Gordillo, Hernandez Galicia's power was believed to represent a challenge to the president, and his arrest was interpreted as an assertion of the president's authority. He was freed from prison after Salinas left office.
Murillo denied that Gordillo's arrest was politically motivated and said it could not be compared to Hernandez's case.
"This was a very clear investigation and we will have more of them," he said.
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.