Still image of a video that debunks the Mexican government's official version of the massacre of Apatzingán.

Social media in Mexico is buzzing over an investigation by independent journalist Laura Castellanos published on news site Aristegui Noticias, magazine Proceso, and TV broadcaster Univisión, among others. In it, she debunks authorities’ version of a deadly shooting that took place in the city of Apatzingán, Michoacán, during the wee hours of January 6, 2015.

According to the investigation:

El pasado 6 de enero, policías federales a bordo de decenas de vehículos irrumpieron en el centro de Apatzingán y abrieron fuego contra civiles, lo que causó la muerte de por lo menos 16 personas y heridas a muchas más. Sin embargo, Alfredo Castillo, entonces comisionado federal de Seguridad en Michoacán y quien acaba de ser nombrado director de la Conade (Comisión Nacional de Cultura Física y Deporte), sostuvo que tales hechos fueron producto de un “fuego cruzado” entre civiles.

Last January 6, federal police riding dozens of vehicles burst into Apatzingán's downtown plaza and started shooting civilians, killing at least 16 people and injuring several more. Nonetheless, Alfredo Castillo, then federal commissioner of security in Michoacán and recently named director at Conade (Mexico's National Commission for Physical Culture and Sport), maintained that the events were caused by “friendly fire” among civilians.

Castellanos’ work was based on the recorded testimonies of 39 people, including survivors, local witnesses, victims’ families and medical staff reports. They described how federal police, while yelling “kill them like dogs”, started shooting hundreds of members and followers of the State's Rural Force who were having a sit-in protest in front of city hall.

In 2013, the State Rural Force began as an armed self-defense group that aimed to combat the violence from the Templar Knights‘ criminal cartel. In May 2014, it was “legalized” by Alfredo Castillo, who is now accused of being behind the attack.

Warning: The Spanish-language video below, “Unpublished Video: The Massacre of Apatzingán,” contains graphic scenes of violence.

Twitter users began discussing the investigation under the hashtag #FueronLosFederales (it was the federal police), which became a trending topic list in Mexico over the weekend of April 18 and 19:

#FueronLosFederales ahora la gente no solo debe cuidarse d criminales tambien s la autoridad q se supone debe proteger @EPN me dueles Mexico

— vicko deah (@v1ck0o) April 19, 2015

It was the federal police: now people should not only be careful with criminals but also with authorities who are supposed to be protecting President Peña Nieto. Mexico hurts me

#FueronLosFederales en #Apatzingan y ahora andan en @CONADE como si nada. pic.twitter.com/ebzphjlWuB

— Jenaro Villamil (@jenarovillamil) abril 20, 2015

It was the federal police in Apatzingán and now they are at the National Commission for Physical Culture and Sport pretending as if nothing happened

Hours before the publication, the news site Aristegui Online — lead by journalist Carmen Aristegui — suffered two DDoS attacks that left it down for approximately 12 hours, according to anti-censorship organization Article 19 and several Twitter users:

#ALERTA: Ataques DDoS dejan fuera de línea a @AristeguiOnline, un día antes de publicar #FueronLosFederales. http://t.co/Jbud6CZjG1 — ARTICLE19 MX-CA (@article19mex) April 20, 2015

WARNING: DDoS attacks take down @AristeguiOnline one day before publishing #FueronLosFederales

Sigue hackeado http://t.co/CEuRbNe8nU#FueronLosFederales@article19mexpic.twitter.com/7tZUOBK3mR

— Enrique D. (@kikesma) April 19, 2015

Still hacked

After the news started spreading, many recalled other extrajudicial killings reported during President Peña Nieto's term:

Iguala, Tlatlaya y Apatzingán son el mismo modus operandi criminal #FueronLosFederales#QuienTemeTeCensura — Antonio Helguera (@ahelguera) April 20, 2015

Iguala, Tlataya and Apatzingan have the same criminal modus operandi #FueronLosFederales #QuienTemeTeCensura (those who fear you censor you)

La investigación de @lcastellanosmx sobre #FueronLosFederales muestra q las masacres son una política oficial concreta — Julio Hdz. López (@julioastillero) April 20, 2015

The investigation by @lcastellanosmx of the federal police shows that the massacres are an official and concrete policy

Toda esta sangre algún día puede ser la de tus hijos #FueronLosFederales y no olvidemos Tlatlaya y Ayotzinapa https://t.co/oxkHhegNZy

— alberto rodríguez (@bijuunine) April 19, 2015

All this blood could one day belong to your kids #FueronLosFederales (it was the federal police) and let's not forget about Tlataya and Ayotzinapa

Given the grave accusation, users demanded accountability from the government and made gestures of of support to journalist Laura Castellanos:

Queremos respuestas. Pero desde un inicio estrategia de gobierno de @EPN ha sido callar frente a la verdad e ignorarnos. #FueronLosFederales

— El Grito Más Fuerte (@elgritomas) April 20, 2015

We want answers. But since the beginning President Peña Nieto's government's strategy has been shutting up the truth and ignoring us.

Terrible enterarse de algo como esto. Mi apoyo a @lcastellanosmx. #MasacreApatzingán#fueronlosfederaleshttp://t.co/KlzjWU5ian — Alejandro Solalinde (@padresolalinde) April 19, 2015

It's terrible to find out something like this. My support to @lcastellanosmx. #MasacreApatzingan

La única salida a las masacres perpetradas por el Estado es el procesamiento de sus ejecutores y de quienes las ordenan #FueronLosFederales

— Jesús Robles Maloof (@roblesmaloof) April 19, 2015

The only way out of the state-sponsored massacres is to bring the executioners and their bosses to justice.

The reporter herself as well as some netizens wondered if the wave of violence by those who are called to protect the people will continue or if the guilty will ever be brought to justice. They have good reasons to be wary, considering the level of impunity that reigns within the country. According to the Global Impunity Index, Mexico ranks second highest in the world.

Esta obra de @monerorape ilustra dolorosamente el caso #FueronLosFederales. Gracias, gran amigo. #MasacreApatzingán. pic.twitter.com/xosJljuFdC

— Laura Castellanos Mx (@lcastellanosmx) April 20, 2015

This piece by @monerorape painfully illustrates the #FueronLos Federales case. Thank you, great friend

¿Qué sigue? #FueronLosFederalespic.twitter.com/1zCmWwt1o6

— Enrique D. (@kikesma) April 20, 2015

What's next?

After Castellano's news report spread, the federal government announced an investigation of the developments in Apatzingán. Follow more reactions under the hashtag #FueronLosFederales.