Can my child get in trouble for having sex with a minor?

My son has an order to appear in court for having sex with an underage girl who is not American citizen. She is Mexican living in this country illegally. Her parents took her to the doctor and realized that she’s not a virgin. They reported it to the police but the police just came and told my son to stay away from her. I talk to the girl's father and told me that there is someone who is investigating the case. She lied to my son telling him she was 18, as she is not an American citizen does not have an identification card or anything. She admitted in front of the police and in front of her father she lied to my son. My son is 22 and she is 15. A month has passed since the incident and the police did not come and no one to pick up my son. The girl's father said that if electronic system for travel authorization in their hands the fate of my son does not condemn him, as my son and daughter love each other and want to live together. The problem is that the police are aware.