The FBI is assisting the investigation into the disappearance of 43 missing college students in Mexico, a U.S. government official tells NBC News.
American scientists are helping analyze DNA evidence at the request of the Mexican government, the source said. So far, only one body of the missing 43 students has been officially identified by Mexican authorities. The others are feared dead after federal police arrested three suspected drug traffickers who allegedly confessed to the killings.
But now, there are also questions about what the Mexican government initially knew about the case.
"Nothing was an accident that night," said Anabel Hernandez, an investigative reporter who has previously authored a book on Mexico’s drug war. She is now a fellow the University of California-Berkeley’s Center for Investigative Reporting.
Hernandez said she’s uncovered thousands of pages of documents from the state investigation into the students’ disappearance on Sept. 26, which had not been publicly available.
Prosecutors allege that corrupt local officers had turned the students over to the Guerreros Unidos drug gang, following orders from José Luis Abarca, the mayor of Iguala, a city in the state of Guerrero about a three hours’ drive south of Mexico City.
The mayor, his wife and dozens of local officers have been arrested. But Hernandez now believes federal authorities played a role in the students’ disappearance, which would contradict the government’s version of events.
"The government knew exactly what was happening,” she said.
Hernandez claims the documents and cell phone videos taken by some of the surviving students reveal that federal police were also at the scene that night and had been monitoring the students before the confrontation — although it’s not clear why.
Her allegations were first published last month in a story co-authored by journalist Steve Fisher for the Mexican magazine Proceso.
The Mexican federal police referred all questions about the allegations to the attorney general’s office, which repeatedly declined to comment to NBC News.
But Attorney General Jesus Murillo Karam told "CNN En Español" that he had not seen the evidence Hernandez cities — and that he did not know where it came from.
The students’ whereabouts and questions about the government’s response have sparked protests for months throughout the country and have drawn international attention.
Relatives of the missing students are demanding answers from Mexico’s president, Enrique Peña Nieto, who is scheduled to meet with President Obama in Washington on Jan. 6.