Mexico City: Mexico on Wednesday ordered the arrest of the mayor of the city of Iguala, his wife and an aide, charging they masterminded last month`s attack that left six students dead and 43 missing.
Carrying torches and candles, tens of thousands of people marched through Mexico City and other cities to protest the disappearance of the students.
"We shall overcome," protesters shouted with clenched fists in the air. Marching were students, teachers, farmers and activists joining relatives of the missing students.
"They took them away alive. We want them back alive", ran another slogan.
The march was peaceful. Town hall gave the figure of participation at 45,000.
Protesters carried large black and white photos of the missing and called out their names, one by one, as if in a roll call in class, followed by the world "present."
Protesters banged drums, strummed guitars and blew whistles.
"I am indignant over what happened. They could have been my students, my brothers, my children," said Jorge de la Pena, a psychology professor at the National Autonomous University of Mexico.
Mexican authorities have searched in vain for any trace of the teachers college students who disappeared on September 26, in a case that has sparked national and international outrage, including mass demonstrations that saw the Iguala city hall torched Wednesday.
"Arrest warrants have been issued for Iguala mayor (Jose Luis Abarca)," as well as his wife and public safety chief, "as the individuals who likely organized the events that took place in Iguala," Attorney General Jesus Murillo Karam told reporters.
Abarca "gave police the order to confront" students, who were known for frequent protests, so that they would not derail a public event by his wife, the head of a local state children`s protection charity.
Authorities say corrupt officials and police worked hand-in-hand with the Guerreros Unidos drug cartel in the attack, which could prove to be one of the worst slaughters that Mexico has witnessed since the drug war intensified in 2006.
The mayor`s wife, Maria de los Angeles Pineda, is a sister of at least three known drug traffickers, and the couple has ties to Guerreros Unidos, authorities said.
Searchers are still desperately combing the area for the missing students by land and air, almost a month later.Authorities say Iguala`s police force shot at buses carrying the students and handed them over to officers in the neighboring town of Cocula, who then delivered them to the Guerreros Unidos drug gang.
On Wednesday, protesters in Iguala set fire to the city hall building in the latest display of rage over the unsolved disappearances.
Thousands of teachers and students demonstrated, an unspecified number of whom torched the building, which at the time had no workers inside, an AFP reporter said
It was the second incident in which demonstrators set fire to local buildings in Iguala in as many days.
On Tuesday, 500 teachers set fire to a political party office in the capital of Guerrero state, Chilpancingo.
Armed with pipes and sticks, the protesters burst into in the state headquarters of the Democratic Revolutionary Party demanding the resignation of state governor Angel Aguirre.
The protesters burned computers and documents, but no one was hurt.
Authorities have found several mass graves in Iguala but say 28 sets of remains examined so far do not correspond to the students.
This week, the government announced a $110,000 (87,000 euros) reward for information in the disappearance of the students.
A total of 36 municipal officers in Iguala have been arrested in the case, along with 17 Guerreros Unidos members and their boss.
Mexican authorities last week announced the arrest of the "maximum leader" of the Guerreros Unidos gang, Sidronio Casarrubias, at a police checkpoint on a highway between Mexico City and the nearby city of Toluca.