In late 1940 he was again arrested in Zagreb because of a congratulatory telegraph to Jozef Tiso , president of the newly formed Slovak Republic ( 1939 â `` 1945 ) , signed by a number of Croat nationalists . In late 1940 he was arrested in Zagreb due to a congratulatory telegraph to Dr. Jozef Tiso , president of the newly formed Slovak Republic , signed by a number of Croat nationalists .