The politically oriented hacking group, Anonymous, has released 1GB of what is says are private emails and documents from an executive of a US defence company that sells unmanned aerial vehicles to the police and military.

The documents were publicised in a post on Pastebin, with links leading to the actual material on another website. The material purportedly belongs to Richard Garcia, a senior vice president at Vanguard who was a Federal Bureau of Investigation (FBI) special agent for 25 years.

Anonymous took special delight in the breach, as Garcia is director of InfraGard, an organisation that liaises between private sector companies and the FBI. A group affiliated with Anonymous called LulzSec breached and defaced one of InfraGard's websites belonging to its Atlanta chapter in June.

LulzSec said the attack was in retaliation for a call for tougher action against hackers by the North Atlantic Treaty Organisation and US President Barack Obama.

Anonymous said the "leak contains internal meeting notes and contracts, schematics, non-disclosure agreements, per personal information about other VDI employees and several dozen 'counter-terrorism' documents classified as 'law enforcement sensitive' and 'for official use only.'"

A cursory look through some of the material shows it does seem to match the description from Anonymous. One of the emails shows Vanguard's chief executive responding to a Department of Justice contact regarding the suitability of its ShadowHawk drone for use by the US Marshals service.

The ShadowHawk is a small unmanned aerial vehicle that stay aloft for up to three hours to conduct surveillance. At an altitude of 700 feet or higher, the devices is not heard by someone on the ground. For military and law enforcement, a ShadowHawk can be equipped with a grenade launcher or shotgun.