How safe is the US society?

Tweet

Two years ago, Zhang yingying, a visiting schorlar from China went to the US for studying, then she was seduced by the bad guy called Christensen, he pretended to be a policeman dressed casually, and seduced Zhang into his car. Then he drove her apartment and raped her, he tortured the girl and killed her brutally and finally made her body apart. Two years later, now, Zhang's body is still missing. Recently, I mean around a year, there are always news and posts claiming that American society is not safe, it seems that going to America is not a wise option for people in China. So, I really wonder is American society safe or not? And what's your view on Chinese people abroad?