Police in the south German state of Bavaria have detained a suspect during a fire at Adolf Hitler's Alpine mountain retreat, the Kehlsteinhaus, also known as the Eagle's Nest. Dispatchers in Traunstein received a fire alarm from the building at 21:15 (19:15 GMT) on Friday, and firefighters found it engulfed in flames. The Nazi dictator used the retreat, which lies above the town of Berchtesgaden, as a part-time seat of government and met commanders there to plan the invasion of the USSR in 1941. A criminal investigation is under way to determine whether the suspect is connected to the fire.