An annual report this week by the State Department described "significant human rights issues" in North Korea
The gunman opened fire at police on Wednesday, injuring four policemen before he was arrested.
Police said he was a member of the Reichsbuerger (Reich citizens) movement, which maintains that the World War Two German Reich continues to exist.
"The seriously injured member of the North Bavaria special forces died in a clinic in the early morning hours (20.10.2016) due to his heavy gunshot wounds," police said in a statement on Thursday.