Unia Stowarzyszeń i Organizacji Polskich w Ameryce Łacińskiej, USOPAŁ) the largest Polish immigrant organization of South America.
In 1952, he arrived in Paraguay, taking advantage of President Federico Chaves' immigration program, which allowed 18,000 families from Europe to settle in that country.
According to Polish journalists Jerzy Morawski and Mikołaj Lizut, Kobylański had a good relationship with Paraguayan president, General Alfredo Stroessner.
In 2004, the investigative section of the Instytut Pamięci Narodowej (IPN) began[7] legal proceedings to determine if the accusations of handling over a Jewish family named Szenker to the Gestapo were true.
In April 2006 the chief of the investigative section of the IPN, Witold Kulesza, reported: "so far, we have not found any evidence of the charges that... Jan Kobylański, handed over to the Germans a married Jewish couple.
According to his version, Gestapo officers went to the hostel where he stayed with his family, and showed him his personal notes, which he handed to Kobylański, hoping that it would help in the preparation of false documents.
According to documents collected by the Prosecutor's Office in Warsaw, the evidence that Jan Kobylański was the perpetrator in the denunciation of the Szenkers family cannot be proved.
[citation needed] In 2005, Mikołaj Lizut wrote in the Gazeta Wyborcza that Jan Kobylański falsified documents of the Red Cross, that he was a prisoner at Auschwitz, Mauthausen, Gusen, Gross Rosen, and Dachau concentration camps.
[12] In December 2007, the minister of Foreign Affairs, Radosław Sikorski, sent a message to Polish embassies abroad to discontinue contact with Kobylański.
[13] In late November 2008, two independent internet services reported that Kobylański was going to open a legal case against Polish politicians and journalists (among others against Adam Michnik, Jerzy Baczyński and Ryszard Schnepf)[14] on charges of slander.