Driving down 55 zone 2 lane road.?

Lexus is going 45. P in a legal ping zone, however after clearing the car the lexus aggressively accelerates and front right my truck hits the back left of their car. Policeman gives me contact information from their insurance and i do not get a citation. He tells me to leave and I didnt not ask officer who if the other party was responsible. Did they get a citation, or are both of us not responsible and other party try to get a claim off my insurance. thanks