Argentine police are investigating a possible manslaughter Saturday after a bus ran off a road into a ravine, killing 10 people and injuring 50 in the northwestern part of the country.
The first reports indicated brake failure caused the accident on Friday.
But police said the double-decker bus appeared to be overloaded with passengers. Some witnesses said it was traveling too fast for the hilly highway where it crashed.
"There are 10 dead -- seven men and three women -- among them a six-month-old baby and a six-year-old girl," said a police report.
The bus was traveling from Villazon in Bolivia to Buenos Aires when the accident occurred in Argentina's Jujuy province, which borders Bolivia.
"The driver told me that the brakes locked up," local prosecutor Rodolfo Fernandez, who is leading the investigation, told local media.
The driver, the relief driver and the bus hostess, all Bolivians, survived the crash and are under arrest while they are being investigated for "involuntary manslaughter," a judicial source said.
Passengers "reported that the bus was traveling at high speed and apparently that could have caused the fatal accident," said criminal prosecutor Alejandro Maldonado.
Among the passengers were at least 48 Bolivians, five Argentines, three French, three Peruvians, two Germans, an Englishman, a Canadian and a Spaniard.
The injured were transported to a local hospital, which said 34 were being hospitalized, including five in intensive care and in serious condition.
The accident occurred on a stretch of highway known for curvy slopes that require prolonged braking, Nebhem said.
Forensic experts are trying to identify the bodies, some of which were mutilated by the collision, he said.