这样出尔反尔，可做不了一个好证人啊。
Seriously, you can try to make a police report. I am just not sure what you have to say. Is it about the incident in China or an incident happened during a phone call between the US person and Chinese person? You have to have who, when, where, what, how.
Since I am not sure the 5W's, proceed at your own risk.
