Wire reporting: (AP, via CNBC)

A fire Friday night engulfed the Kehlsteinhaus, the mountaintop guesthouse known as the Eagle’s Nest above Berchtesgaden in Bavaria, German police said, and a man was detained as a criminal investigation began^1,2,24.

Upper Bavaria South police said crews were alerted about 9:15 p.m. local time and found the building fully in flames; no one was inside and no injuries were reported^1,24.

BBC reported about 200 emergency workers were sent and that difficult terrain slowed the response^2,1.

BBC said police detained a 33-year-old German man, with German media saying he was stopped on a motorcycle near the scene^2,24.

Prosecutor Rainer Vietze said a psychiatric report found signs of possible mental illness and that diminished responsibility might be assumed, BBC reported; a political motive was also being considered, he said, while stressing the inquiry was early².

Police official Gerhart Holzinger said there was nothing so far to suggest further suspects². Al Jazeera said police were examining whether the detained person was connected to the fire²⁴.

Completed in 1938 and later run as a restaurant and exhibition, the site survived World War II largely intact^1,5,24. CBS News said the site is a tourist restaurant and beer garden¹. CNBC said the local tourism authority was unsure whether parts of the building could be salvaged, and that police later said it burned down almost completely⁵.

Bavaria Interior Minister Joachim Herrmann said the site would not remain a ruin and that remembrance work would continue². The cause had not been officially announced²⁴.