- "Now no one is going to return him to me," father says
- Mexico's attorney general confirms that a missing student's remains were identified
- Alexander Mora Venancio, 19, is one of 43 students who went missing in September
- Authorities say they were kidnapped and killed on orders of the local mayor
Ezequiel Mora's voice trembled as he revealed the news.
Investigators used DNA testing from a bone fragment to confirm that they'd found his 19-year-old son's remains in a plastic bag, he told CNN en Español.
"They gave me the news that my son is now ... he is now dead," Mora said.
Alexander Mora Venancio, the youngest of eight siblings, was one of 43 students from a rural teacher's college in Mexico's Guerrero state who went missing on September 26.
Authorities have said they believe the students' remains were burned at a landfill, then placed inside plastic bags and thrown into a river. But so far, Alexander Mora's remains are the only ones that have been identified.
For weeks, his family has been pushing for answers about the students' whereabouts. Alexander's friends from school have donated money to help them as they wait for a response, his father told CNNMexico.
"Everyone comes and gives me their support ... but now no one is going to return him to me," he said.
Federal authorities say they heard confessions from drug traffickers indicating that the college students were rounded up on the orders of a local mayor and then delivered to the drug gang to be murdered.
Mounting fury over government officials' response to -- and possible role in -- the students' disappearance has fueled demonstrations across the country.
At a protest in Mexico City on Saturday night, a group of parents said the search for the rest of the group is not over, despite the announcement.
"My son, wherever you are, I'll keep looking for you, even if my heart is breaking by the news," one father said.
Felipe de la Cruz, a spokesman for the students' families, said they received confirmation of Alexander Mora's death Friday from Argentine forensic experts who are working on behalf of the families. But he said the families still believe the remaining students are alive.
"If these murderers think that with a DNA match of one of our boys, we are going to stop and cry, we want to tell them that they have been mistaken, that after today, this day of action will continue until we find the remaining 42 alive," he said.
At a news conference Sunday, Mexican Attorney General Jesús Murillo Karam confirmed that Alexander Mora's remains had been found. He showed images of the garbage dump and the river, read from a detailed DNA analysis from scientists at Austria's Innsbruck University and vowed that the investigation would keep going.
"Based on my own conviction and the orders of the President, we're going to continue with this investigation until we detain all the culprits," Murillo said.
So far, 44 police officers have been arrested inthe case, and authorities are searching for 16 others, he said.
Authorities have accused Iguala Mayor Jose Luis Abarca of being the "probable mastermind" in the students' disappearance. He's been charged with six counts of aggravated homicide and one count of attempted homicide and is now being held in a federal prison, authorities said.
In all, at least 80 people have been arrested in the disappearances and the deaths, and the governor of Guerrero has taken a leave of absence amid scorching criticism that he responded too slowly to what's been called one of the most serious human rights abuses in recent Latin American history.
Families of the missing students have said for weeks that they don't accept the official version and demand proof of what happened.
This weekend, Alexander Mora's cousin told CNN en Español that she was unconvinced by the DNA match.
"I don't believe he's dead," she said. "What about the rest of them? I feel like they're just deceiving us."