One of the Spanish instructors on the bridge when the teenager plunged 40 meters to her death has told police the girl jumped before her harness was clipped on to the bungee cord.
An instructor told Spanish television channel RTVE that she had said. "No jump. No jump," but that the girl may have misheard and thought she said "now jump".
Police have opened an investigation into the death, which was the second fatal bungee accident to occur in Spain in the last month.
The accident on Monday evening at 8.30pm occurred on a viaduct over a dry river bed outside the town of Cabezón de la Sal, in Spain's northern region of Cantabria.
The girl, whose name has not been released was with a group of young people staying at a campsite on an organized adventure holiday with an established tour group.
She was the last one out of the group of 13 young people to take her turn at the bungee jump platform, according to a report in El Pais.