If you talk to a police officer about something, can you ask them not to tell your parents?

The other day I was at my girlfriends house and her mom came home while i was there. I ran out the front door and sped away and her mom called the cops and now there is an investigation on whose car my car belongs too since my girlfriend lied to her mom and said she doesnt know who it was. Now the police (according to her mother) have reported that they saw my car at my high school today since I drove my car to school today. We have an on duty police officer in our school at all times and my girlfriend plans on going to the officer and telling him the whole situation and asking him to tell her mother that it wasnt me it was a friend of this kid that goes to our school, lives near her, and is in our grade. Can the officer agree to my girlfriends terms and tell her mother what she asks? Or is he required to tell her mom what happen? We werent doing anything bad, nothing even ual since AP exams are here we were actually studying but her mom is very strict about boys.