A modified consumer drone was used in an attack on an electrical substation in the US last year, according to a report from the FBI, Department of Homeland Security and National Counterterrorism Center. The report, which is being circulated to law enforcement agencies in the US, highlights the incident at a substation in Pennsylvania last year as the first known use of a drone to target energy infrastructure in the US. The location isn't specifically identified, but the drone crashed without causing damage. The drone was modified with a trailing tether supporting a length of copper wire. If the wire had come into contact with high-voltage equipment it could have caused a short circuit, equipment failures and possibly fires.