It's been widely suspected for decades that North Korea's political elite - including members of the ruling Kim family - would obtain Western visas under false pretenses, but for the first time, Reuters has published images of a fraudulently obtained Brazilian passports that North Korean leader Kim Jong Un used to apply for visas to visit western countries.

Over the years, specific details about the Kim family's strategy for covertly traveling abroad have proven elusive - until now. Previously, images of a fraudulent Dominican Republic passport belonging to Kim Jong Nam, the half-brother of Kim Jong Un who was assassinated two years ago, surfaced after his death...

Reuters published a photocopy of Kim Jong Un's passport...

Brazil's foreign ministry said it was investigating.

A Brazilian source, who spoke on condition of anonymity, said the two passports in question were legitimate documents when sent out as blanks for consulates to issue.

Unnamed Western security officials say the passports reveal the ruling family's preparations for a possible "escape route" should they ever lose their grip on power.

"They used these Brazilian passports, which clearly show the photographs of Kim Jong Un and Kim Jong Il, to attempt to obtain visas from foreign embassies," one senior Western security source said on condition of anonymity. "This shows the desire for travel and points to the ruling family's attempts to build a possible escape route," the security source said.

Four other senior Western European security sources told Reuters that the two Brazilian passports with photos of the Kims in the names of Josef Pwag and Ijong Tchoi were used to apply for visas in at least two Western countries.

Though it's unclear whether any visas were actually issued. The passports may have been used to travel to Brazil, Japan and Hong Kong. A Japanese newspaper reported in 2011 that KJU visited Tokyo in 1991 - when he was still a child - using a Brazilian passport, which is before the issue date on the two Brazilian passports obtained by Reuters.

Both passports, which were good for 10 years, were stamped with "Embassy of Brazil in Prague" with a Feb. 26, 1996, issue date. Facial recognition technology has reportedly confirmed the photographs were those of Kim Jong Un and his father.

So little is known about KJU that even the date of his birth is disputed. The passport issued for him in the name of Josef Pwag had a Feb. 1, 1983 date of birth. If that's an accurate birth date, that would mean Kim is 35. KJU is known to have been educated at an international school in Berne, Switzerland, where he reportedly pretended to be the son of an embassy chauffeur.

Kim Jong Il's passport was issued in the name Ijong Tchoi, with a birth date of April 4, 1940. Kim Jong Il died in 2011. His actual birth date was in 1941. Both passports list the birthplaces of the two men as Sao Paulo, Brazil.

Reuters was unable to confirm that the passports hadn't been tampered with.