Biro - Richter. 1907 Croatia

I'm looking for m roots, in Croatia. Is here anybody who could help me? My grandfather was Bogdan Biro, he had a brother Ljubo who was an artist (painter, sculptor?) and he lived somewhere in Florida, US. Ljubo died about 5 years ago.

Their father was Vilim. He is a mistery to me, because I was told that he (or his father) changed his last name from Richter to Biro (meaning "judge" in german and hungarian).

Thank you for any information!