Johannesburg - An 18-year-old man was arrested on Sunday after he was allegedly caught in the act of raping his 5-year-old niece, Soweto police said.Warrant Officer Kay Makhubela said the toddler's mother walked in on the man allegedly raping the child in Mofolo North on Saturday night."She walked in on the man raping her child and immediately called the police," Makhubela said.The girl was taken in for medical observation."The attending doctor found that it was not the first time the child had been raped. The girl is now in counselling and is being treated for injuries."The suspect was due to appear in the Protea Magistrate's Court on Monday.