German police have arrested a suspect in connection with a fire at the Eagle's Nest, the mountain retreat built for Adolf Hitler in the Bavarian Alps. The blaze broke out on Friday night, according to a statement from Upper Bavaria South police.

Emergency services were alerted at about 9:15 p.m. local time to a fire at the building, also known as the Kehlsteinhaus, which sits on the peak of the Obersalzberg. When firefighters reached the scene, police said, the structure was "completely engulfed in flames." Nobody was found inside and no injuries were reported.

Crews had trouble getting fire trucks to the site because of "the local conditions," authorities said.

Investigators quickly identified a possible culprit. "Shortly after the fire broke out, a suspect came into the focus of investigators," police said in their statement. The cause of the fire is now the subject of a criminal investigation, and one person has been taken into custody.

Prosecutors said the suspect is a 33-year-old German citizen with ties to the Berchtesgaden area, though he does not live there at present. The Associated Press reported that he has been questioned. Prosecutors said he showed signs of mental illness and would be sent to a psychiatric facility. They added that they would also examine whether there was a political motive, given the history of the building. Police said there were no current indications that anyone else was involved.

The Eagle's Nest stands at an elevation of 6,017 feet. It was completed in 1938 and was used by Hitler on occasion as a temporary seat of government. The building escaped Allied bombing during World War II, which left it largely in its original state.

In the years since, it has become a popular tourist destination and also operates as a restaurant and beer garden. Its website describes it as "one of the few undamaged monuments of the Hitler era" and says it "stands for the insanity of the regime."

Bavaria's interior minister, Joachim Herrmann, told reporters in Berchtesgaden that the Eagle's Nest will be rebuilt. How the site will look in the future, he said, will be a matter for talks with local officials, historians, preservationists and others. "We're not going to leave a ruin there," Herrmann said, according to the AP. He added: "I think we will be able to find a sensible solution."

Herrmann also stressed that "it is important that we continue to do the work of remembrance."