This report is based on the leaked recording of the conversation. Last words from the pilot before the plane slammed into a mountainside said, "Complete electrical failure, without fuel."

Before this, the plane was instructed to wait seven minutes because another plane was prioritized which had mechanical problems. It was also heard in the conversation that the plane was flying at a 9,000 feet altitude, The Guardian reported.

The recording obtained on Wednesday by the Colombian media showed fuel problems as the cause of the crash. This matched with how the plane looked in the crash area. There was a lack of explosion which indicates that the plane really was running out of fuel before the tragedy happened. Experts said the plane was flying at its maximum range.

Arquimedes Mejia, a rescuer who helped pulled Ximena Sanchez out of the wrecked plane, said in the Associated Press interview that the survived Bolivian flight attendant told him they ran out of fuel and the plane turned off. Sanchez would be interviewed by the investigators in the clinic near Medellin where she is recovering.

According to Alfredo Bocanegra, head of Colombia's aviation agency, "If this is confirmed by the investigators it would be very painful because it stems from negligence," he told Caracol Radio on Wednesday. He also added that evidence initially pointed to an electrical problem, but the possibility of fuel problem was not yet ruled out.

During this time that the real cause of the crash was not yet confirmed, authorities avoid giving any specific cause. The crash was reported killing 71 people out of 77 who have been aboard including Brazil's Chapecoense soccer team who were travelling to Medellin for the Copa Sudamericana finals, as reported by USA Today.

It would be expected that the full investigation will be executed from every single data that could help. The U.S. National Transportation Safety Board is joining the investigation since the plane's engines were made by an American manufacturer.