Tens of thousands took part in a mass march down the streets of Mexico City on Wednesday, the latest in a series of protests linked to the disappearance of 43 student-teachers who have been missing since September.

According to the Associated Press, "the largely young crowd carried Mexican flags with black mourning bands replacing the red and green stripes, counting off the numbers from one to 43. Protesters also chanted: 'They took them away alive, and alive we want them back.'" Many parents of the missing youths, who were allegedly abducted in the city of Iguala on September 26, also joined the demonstration.

Also Wednesday, universities across Mexico began a 72-hour strike to demand justice for the students. TeleSUR reports that the student strike was decided on last week, when the Inter-university Assembly made a decision to paralyze activities at the National Polytechnic Institute, the National Autonomous University of Mexico, the Metropolitan Autonomous University, and the Mexico City Autonomous University.

In addition, religious and civic groups planned to begin a 43-hour hunger strike on Wednesday night.

"The disappearance of the students has detonated all the accumulated pain of the thousands of disappeared people in this country," one 19-year-old university student told the AP.

The Mexican government estimates more than 22,000 people have gone missing during the last eight years of violence between cartels fighting each other and security forces. Human rights groups say the toll could be far higher.

Earlier this week, federal authorities announced they had detained the former mayor of Iguala, who—along with his wife—had been on the run since the day after the students disappeared. Mexico's attorney general last month accused José Luis Abarca of ordering the police to go after the students because he feared they would disrupt a speech being given by his wife, María de los Ángeles Pineda, that same day. Witnesses claim the police shot at the students, who were taking buses back to their campus, resulting in three deaths, before handing the rest over to a local gang.

The New York Times reported that the fugitive couple was "detained by an elite unit of the federal police in a run-down, apparently abandoned house in the working-class district of Iztapalapa, 120 miles north of Iguala, the town where the students disappeared and which the couple presided over in collusion with the Guerreros Unidos drug gang, the authorities have said."