Three missing Mexican students were killed last month in the western state of Jalisco and their bodies dissolved in acid after criminals confused them with members of a rival gang, according to authorities.

The disappearance of the three film students, 25-year-old Javier Salomón Aceves Gastélum and 20-year-olds Marco Garcia Francisco Avalos and Jesús Daniel Díaz, 20, prompted protests from across Mexico, and outrage from the international film community.

They were kidnapped by at least six people, who tortured and killed them, according to Jalisco state prosecutors. 'Subsequently their bodies were dissolved in acid so that no trace of them remained,' the state prosecutors office said.

The last time they were seen alive was after their car broke down. They were seen being forced into another car by two armed men dressed as police officers in Guadalajara, Mexico's second largest city, in the western state of Jalisco.

Three Mexican film students who went missing in Guadalajara, in Jalisco State, Mexico, were kidnapped, tortured, killed and dissolved in acid. Pictured: Jalisco Institute of Forensic Sciences work at a house connected to their disappearance

Javier Salomón Aceves Gastélum, 25, Marco Garcia Francisco Avalos, 20, and Jesús Daniel Díaz, 20, went missing last month, authorities say they were confused for a rival gang of the Jalisco New Generation Cartel

Javier Salomón Aceves Gastélum, 25, Jesús Daniel Díaz, 20, and Marco Garcia Francisco Avalos, 20, are pictured during a press conference Monday after investigators said they were confused for rivals of the Jalisco New Generation Cartel

State prosecutor Raul Sanchez said that two people had been arrested so far in the investigation.

Another official said, on condition of anonymity since he was not authorized to speak to the media, that investigators are analyzing more human remains found on the premises of the building where the young men were dissolved.

'There are no words to comprehend the magnitude of this madness,' Oscar-winning director Guillermo del Toro, a Guadalajara native, tweeted early Tuesday. '3 students are killed and dissolved in acid. The "why" is unthinkable, the "how" is terrifying.'

On Monday night, families of the deceased protested to reject the official version about the disappearance of their loved ones outside of the Jalisco state Governor's residence in Guadalajara

Prosecutors said the youths, who were students at University of Audiovisual Media, were confused with members of a another gang by gunmen from the Jalisco New Generation Cartel (CJNG), which has become the most powerful in Mexico, according to U.S. authorities.

Criminal groups in Mexico are known for kidnapping, torturing, dismembering and even dissolving their victims in acid and many of the remains are dumped in clandestine graves.

Relatives and friends of three missing students from the University of Audiovisual Media, place candles during a demonstration to reject the official version about the disappearance of their loved ones outside of the Jalisco state Governor's residence in Guadalajara

Oscar winning director Guillermo del Toro, a Guadalajara native, tweeted his anger at the senseless and brutal slayings

In 2014, 43 student teachers disappeared in the southern state of Guerrero and the government said they were kidnapped by police who handed them over to a criminal group that killed them and burned their bodies.

International observers objected to the government's investigation and the case shook the administration of President Enrique Pena Nieto, who has seen his popularity decline sharply amid corruption allegations and a spike in violence.

More than 25,000 people were murdered last year in Mexico. Homicides hit their highest level in records going back 20 years.