A bit more information on the case. See the article that appeared today, below. This states the facts of the case. It is also worth adding that the State authorities in Michoacán have not been answering calls from family of the 3 who were kidnapped.
We know that 2 of the three (Ana Belén and Diego) are psychology students at the Autonomous University of Mexico City. The three are members of the Citizens Movement: Luis Enrique is also the coordinator for the Federal District (i.e. Greater Mexico City) Youth Movement, responsible for the circle for study of progressive and director for the inter-party accord. He is also at the same University where he studies communications.
There are also some posts in English (and more in Spanish) at http://nomasvictimas.org/http://nomasvictimas.org/
The petition site is still live at http://www.change.org/es/peticiones/ay%C3%BAdenos-a-encontrar-a-ana-bel%C3%A9m-s%C3%A1nchez-diego-maldonado-y-luis-casta%C3%B1edahttp://www.change.org/es/peticiones/ay%C3%BAdenos-a-encontrar-a-ana-bel%C3%A9m-s%C3%A1nchez-diego-maldonado-y-luis-casta%C3%B1eda
The following article is from La Jornada, a reliable Mexican daily newspaper La Jornada 13 Sept. Morelia Michoacán, Mexico
Families of three young people, Ana Belén Sánchez Mayorga, Diego Antonio Maldonado Castañeda y Enrique Luis Castañeda Nava, forcibly ‘disappeared’ on 22th July in the municiplaity of Paracho after taking art in the Festival of Balloons of Cantoya, went to the Michoacán State Procurator for Justice Office (State Attorney) to press for the matter to be investigated. It is known that the three were taken from the hotel where they were were staying and that the hotel administration did not report the incident to the authorities. The three young people, from Mexico city, were sent by the company KidScience, contracted by the State Council for Science, Technology, and Innovation, so that they could provide a workshop before the balloon festival. They arrived Wednesday 18th of July and lodged at the Santa Fe Hotel in the centre of Paracho. They delivered the course for children during the next three days and on Saturday 22nd, in the evening, after the inauguration of the festival, were in the bar of the hotel where it seems they were in argument with persons who tried to molest the young woman who is a psychologist. The individuals left but hours later arrived with an armed group which took the three from their rooms by force. The hotel administration was maintained silence and closed the hotel for two weeks. Unofficial sources say assert that the kidnappers were members of a criminal band that operates in the area of the Purépacha plateau. Laura Beatriz Castañeda, mother of Diego, confirmed in a telephone interview that the staff of the State Procurator’s office only said that it is possible that the victims are alive, because bodies have not been found. Then she was taken out via a back door and taken to the bus station to leave without talking to the press.
translation MB original article at http://www.jornada.unam.mx/2012/09/14/estados/042n2est