Leaked documents from the servers of a UK-based surveillance technology company have allegedly brought new evidence that it illegally exported a malicious spyware to Bahrain to target lawyers, human rights activists and politicians.

The fresh data show that Gamma International's FinFisher surveillance technology was installed on 77 computers in a period that stretches between 2010 and 2012, during Bahrain's bloody crackdown on pro-democracy protesters.

It also apparently contradicts earlier claims by Gamma that it does not do business with Bahrain and "added to the growing body of evidence suggesting that Gamma may have have violated UK export laws on surveillance technology" according to Bahrain Watch monitoring group.

The export of a UK-based spyware to repressive regimes has been a matter of controversy in recent months.

Following repeated refusal from the HMRC to reveal whether it was investigating Gamma International's exports, a British court ruled that the the body responsible for enforcing export regulations acted "unlawfully and irrationally".

Gamma International's FinFisher is a sophisticated government spying software used by many countries such as Bahrain, Ethiopia, Egypt and Turkmenistan to monitor dissidents, journalists and human rights activists. It is sold as "governmental IT intrusion and remote monitoring solutions" and operates in at least 36 countries according to the latest Citizen Lab report.

Once the user installs the spyware, "victims' computers and mobile devices can be taken over, the cameras and microphones remotely switched on, emails, instant messengers and voice calls (including Skype) monitored, and locations tracked".

The documents were leaked by an anonymous hacker using the Twitter handle @GammaGroupPR who released 40 gigabytes of apparent internal data from Finfisher on Twitter and Reddit.

The leaks include internal messages between Bahraini government and Gamma's customer service. The Gulf Kingdom's officials complained about FinFisher "not working at all" or bugs and issues that caused them to lose targets. In a message dated 2 November 2011, the Bahraini software administrators asks Gamma:

"Please let us know what to do in this case, as this issue keeps going on and we are losing targets daily with out [sic] our knowledge. and we are sure that we didnt [sic] do the removal. and we cant [sic] stay bugging and infecting the target every time since it is very sensitive. and we dont [sic] want the target to reach to know that someone is infecting his PC or spying on him."

Gamma International has denied selling spyware to Bahrain and claimed that the Kingdom could have been using a stolen demo version of the software. Among those targeted by the surveillance technology is Hasan Mushaima, opposition leader now serving a life sentence in Bahrain and regarded as a prisoner of conscience by Amnesty International and Saeed Shehabi, a London-based political activist who was sentenced in absentia to life in prison in June 2011.

Another prominent target is Mohammed Altajer, a leading human rights lawyer arrested for over 3 months in the 2011 crackdown, who was blackmailed in 2011 with a video of him and his wife having sex in his beach house. The video, included on a CD, arrived in his office along with a threat on 24 January 2011 before the start of the uprising.

Based on the leaked data, Bahrain Watch discovered that FinFisher was installed on his computer that same day, suggesting that Bahraini government was directly behind the blackmail. The video was eventually made public in 2012 after Altajer took part in a UN human rights conference.

"This latest revelations provides strong evidence that not only has Gamma been misleading in its claim of not supplying the Bahraini government, but it did so possessing evidence that its software was being used to target almost solely political dissidents, lawyers and journalists," said Bahrain Watch's Bill Marczak.

A British citizen at the forefront of the uprising who was targeted by FinFisher told IBTimes UK in May that she was "very surprised" that a UK-based company was supplying surveillance technology to oppressive regimes.

"This should be a black and white case," she said at the time. "Has the government taken any steps or actions to stop Gamma from supplying the Bahraini regime with spyware? The answer we believe is to be no because we haven't been provided with the information that can clarify that."