A disgruntled former WikiLeaks employee has destroyed a trove of leaked material taken from his former employer, amid claims he has provided information to US government agencies.

Daniel Domscheit-Berg, sacked from WikiLeaks just under a year ago after a falling out with Julian Assange, told Der Spiegel’s Holger Stark over the weekend that he had destroyed a cache of documents taken from WikiLeaks on his departure, after publicly threatening to destroy them late last week. The material has been in contention between Domscheit-Berg and WikiLeaks ever since, with the German hacker group Chaos Computer Club attempting to mediate the return of the material. The material is said to include at least 3500 submissions, some individually composed of several hundred documents, and keys to their decryption. Among the material, according to Der Spiegel (in German) and later confirmed by WikiLeaks was the US no-fly list — a notorious document that at one stage saw the late Senator Teddy Kennedy repeatedly being stopped and questioned at US airports because of the presence of a “T. Kennedy” on the list. There was also said to be information on a number of far-right groups, and US government internet surveillance arrangements with more than 100 companies.

Domscheit-Berg has changed his position on the circumstances in which he obtained documents more than once, and as the WL Central site has shown, was recently quoted as specifically denying having them.

Equally bizarrely, Domscheit-Berg had suggested whistleblowers whose material he intended to destroy simply resubmit the material to leaks sites. Anonymous whistleblower sites have proliferated since Domscheit-Berg’s departure and Julian Assange’s prosecution by the Swedish government in effect shut down WikiLeaks’ capacity to receive new material. However, security problems have these efforts to ape WikiLeaks, and News Corporation’s disastrous attempt specifically advised whistleblowers that the company would shop them to authorities or even other companies if it was in News Corporation’s interests.

After WikiLeaks, Domscheit-Berg published an inevitably “tell-all” book on his time in the organisation and repeatedly promised to establish his own “Open Leaks” whistleblower site. Earlier this month, Domscheit-Berg finally unveiled the site at the CCC’s Chaos Communications Camp hacker conference and invited attendees to probe its weaknesses. Flaws in the site were revealed within hours.

The call for testing at the camp apparently sparked a falling out with the CCC, which accused Domscheit-Berg of trying to claim the club’s seal of approval for Open Leaks. Its spokesman Andy Müller-Maguhn told Der Spiegel that Domscheit-Berg had been “shameless” in attempting to co-opt the organisation. Müller-Maguhn went further and suggested Domscheit-Berg was “flexible with facts”. “I doubt Domscheit-Berg’s integrity,” Müller-Maguhn concluded. Domscheit-Berg’s destruction of the material may partly have been pique at the CCC’s decision.

In a demonstration not merely of his rage at Domscheit-Berg’s destruction of material but at the bitter nature of the falling-out, Assange immediately released a statement suggesting that Domscheit-Berg had had contact with the FBI and that his wife had had contact with the CIA.

Domscheit-Berg’s destruction of such valuable material must surely entirely wreck the prospects of Open Leaks, which while long-delayed, had established relationships with media partner organisation ahead of the establishment of its secure dropbox system for whistleblowers. His inability to convnce the hacking community of his bona fides, even before his destruction of potentially critical material (assuming that is what he has done, rather than for example provide them to governments), is unlikely to convince would-be whistleblowers that his site is secure and he is trustworthy, even if claims about his links to law enforcement agencies don’t prove correct.