Journalist Glenn Greenwald said Friday that he won’t be participating in Germany’s parliamentary investigation of National Security Agency spying activities unless the probe includes an interview with Edward Snowden.

Greenwald, who won a Pulitzer Prize this year for his reporting on Snowden’s disclosures of NSA surveillance, said that the Germans would be remiss if they didn’t interview the former security contractor, whose temporary asylum in Russia expired this week.

“I am very supportive of any attempt by the German Parliament to conduct a serious investigation into NSA spying on Germans,” Greenwald said in a statement that he posted on Twitter. “Unfortunately, German politicians have demonstrated, with their refusal to interview the key witness in person – Edward Snowden – that they care far more about not upsetting the U.S. than they do about conducting a serious investigation.”

Greenwald made the same point in April, arguing that “it would be incredibly irresponsible for the German Commission to try and pretend to investigate surveillance on German soil without speaking to the one person who knows more about that and is willing to talk to them than anybody in the world.”

Below, Greenwald’s full statement: