WARSAW, Poland — A historian in northeastern Poland says the moss-covered ruins of a German World War II bunker may hide Russia's precious Amber Room, a national treasure that went missing during the war.

The 18th-century Amber Room, made of amber panels and gold leaf, was fitted into Russia's Catherine Palace near St. Petersburg, where it remained until it was looted by Germany's Nazis in 1941.

Tests in September by earth-penetrating radar in the woods near the Polish village of Mamerki suggest there's a small room at the base of a bunker that was the German army's wartime headquarters, according to the head of Mamerki Museum, Bartlomiej Plebanczyk.

The bunker is located about 62 miles from Russia's Kaliningrad region — which was the German region of Koenigsberg during the war and where the Nazis brought the Amber Room in 1941.

Plebanczyk told TVN24 on Friday that he is "almost certain" that the crumbling concrete bunker hides the Russian treasure. He has informed local Polish authorities in the town of Wegorzewo, who will now decide what to do.

Wegorzewo Deputy Mayor Andrzej Lachowicz told TVN24 authorities will try to see what's in the bunker.

"If not the Amber Room, then maybe some other treasure," Lachowicz said.

The British heavily bombed Koenigsberg in 1944. The current whereabouts of the Amber Room is unknown. In a project that took decades, Russian authorities reconstructed a replica of the Amber Room at the same palace.

According to Plebanczyk, a resident claimed right after the war that he saw German trucks bring heavy cases to the bunker. In the 1960s, residents said they saw a top Nazi, Erich Koch, brought to the site from a Polish prison where he was jailed for wartime crimes. Koch was a top official in Koenigsberg until 1945 and authorities believed he knew the treasure's whereabouts, Plebanczyk told The Associated Press.

Last year, other Polish explorers said they had located another Nazi German treasure: a gold train that reportedly went missing at the end of the war in Walbrzych, in what is now southwestern Poland. Some search work was done but no train has been found so far. The search has attracted thousands of tourists to the region.