In the middle of World War II, the Foreign Office in Berlin commanded its diplomats in the Nazi-friendly Nordic country to gather evidence on the dog, and even came up with plans to destroy the pharmaceutical wholesale company of the dog's owner.
Historians had not been aware of the strange footnote to the Nazi period before some thirty files containing parts of the correspondence and diplomatic cables were recently found by a researcher at the political archives of the German Foreign Office.
Klaus Hillenbrand, an expert who has written several books on the Nazi period, was contacted by the historian and examined all of the documents for an article to be published Saturday in daily newspaper Die Tageszeitung.
In an interview with The Associated Press, Hillenbrand called the entire episode "completely bizarre."
"Just months before the Nazis launched their attack on the Soviet Union, they had nothing better to do than to obsess about this dog," Hillenbrand said.
The dog, Jackie, was a mutt owned by Tor Borg, a businessman from the Finnish city of Tampere. Borg's wife Josefine, a German citizen known for her anti-Nazi sentiments, dubbed the dog Hitler because of the strange way it raised its paw high in the air like Germans greeting the Fuehrer with a cry of "Heil Hitler!"
On January 29, 1941, German Vice Consul Willy Erkelenz in Helsinki wrote that "a witness, who does not want to be named, said ... he saw and heard how Borg's dog reacted to the command 'Hitler' by raising its paw."
Borg was ordered to the German embassy in Helsinki and questioned about his dog's unusual greeting habits.
He denied ever calling the dog by the German dictator's name, but admitted that his wife called the dog Hitler. He tried to play down the accusations, saying the paw-raising had only happened a few times in 1933 - shortly after Hitler came to power.
The Finnish merchant ensured the Nazi diplomats that he never did anything "that could be seen as an insult against the German Reich."
The zealous diplomats in Helsinki did not believe him and wrote back to Berlin that "Borg, even though he claims otherwise, is not telling the truth."
The different ministries that were involved in the dog scandal - the Foreign Office, the Economy Ministry and even Hitler's Chancellory - meticulously reported all their findings about the canine.
The economy ministry announced that the German chemical conglomerate IG Farben, which had supplied Borg's wholesale trade with pharmaceuticals, offered to eliminate his company by ending their cooperation with him.
Based on all this support, the Foreign Office was already looking for ways to bring Borg to trial for insulting Hitler, but in the end, none of the potential witnesses were willing to repeat their accusations in front of a judge.
On March 21, 1941, the Foreign Office asked the Chancellory whether to press charges against Borg and five days later they answered that "considering that the circumstances could not be solved completely, it is not necessary to press charges."
There's no evidence that Adolf Hitler was ever told of the case, even if the case made it all the way to his chancellory, Hillenbrand said.
Tor Borg died at 60 in 1959. His company Tapereen Rohduskuppa Oy eventually became Tamro Group, the leading wholesale company for pharmaceuticals in the Nordic countries.
A spokeswoman for Tamro Group, Margit Nieminen, told the AP that the company had not been aware of the story surrounding Borg's dog until the recent archive discovery.