Mexican Attorney General Jesus Murillo Karam said Tuesday the 43 students missing since September were killed and incinerated, according to witness statements and forensic evidence. Only one body was able to be identified and the rest likely never will be after they were burned beyond recognition, the Associated Press reported.

Karam’s press conference outlining the investigation came almost exactly four months after the 43 students disappeared from Guerrero state on their way to protest a Sept. 26 speech by the wife of the mayor of the city of Iguala. Police have arrested 99 people and taken 385 statements in connection with the case, according to the attorney general’s office, including the mayor and his wife. They’re accused of asking local police to detain and dispose of the 43 men. Those officers allegedly turned the students over to a drug cartel, Guerreros Unidos, to be murdered. "The government of the republic deeply regrets these events," ​​Karam said, noting his sympathy for the victims’ families.

According to a video released Tuesday by the attorney general’s office, Felipe Rodriquez Salgado, known as “El Terco,” ordered Patricio Reyes Landa -- “El Pato” -- to do the hit. In the video, Landa said he got the call around 11 p.m.

Landa then called Jonathan Osorio Cortez, nicknamed “El Jona,” and told him to get ready. They contacted other people to help with the plan, which ended up with them cramming the students’ bodies on top of each other in the bed of a small truck. Karam said the gang members then burned the bodies, put them into garbage bags and threw them into the San Juan River, SDP Noticias reported.

The Mexican government has been under fire for its handling of the case, which protesters saw as typical of a corrupt leadership that doesn’t care about them. Thousands of demonstrators held marches across Mexico City and outside a Washington, D.C., meeting between Mexican President Enrique Peña Nieto and U.S. President Barack Obama earlier this month.