Complex sentence: According to Boztepe, his early days in Germany were difficult due to his Turkish heritage--he was a constant a target for racial insults and, more often than not, verbal abuse would escalate into physical abuse.
Split into simpler sentences: According to Boztepe, his early days in Germany were not easy due to his Turkish heritage. He was a constant a target for racial insults, and more often than not, verbal abuse would often turn into physical abuse.