BUENOS AIRES - The driver of the train that crashed in Buenos Aires over the weekend with 99 passengers injured was charged by a federal judge Tuesday as video footage showed him falling asleep at the wheel.

Julio Cesar Benitez, 45, was arrested and charged for his alleged role in the Saturday accident, as the train was pulling into the city's Once station, according to state news agency Telam.

Judicial sources said Benitez may be charged with causing severe harm due to negligence.

Video footage showed Benitez yawing repeatedly and appearing to doze off several times during the journey. But tests showed he was not under the influence of alcohol.

Benitez underwent medical tests, including DNA tests to match his blood with that found on the train's black box, which was later found in his bag.

"I felt I was losing too much blood and I was trying to recover my belongings that spread all over the floor," Benitez said in his testimony Monday.

Benitez said the train failed to stop as it entered the station, indicating that the braking mechanism was at fault. But he also said he had blurred memories of the event.

Related: