By Fatma Younis
Spanish investigators have suggested that human error may have caused the high-speed train crash that killed at least 68 people, with control centre staff being questioned over what officials described as an "inexplicable human error."
Death toll rises
The disaster, which occurred on a high-speed line, has left at least 68 people dead and many more injured. Rescue operations continue at the scene.
Focus on control centre
Authorities are focusing on the actions of control centre personnel, whose decisions in the moments before the crash are under scrutiny. The term "inexplicable human error" has been used to describe the potential cause.
