Cheating with a mobile phone, can the police go to the telecom to check the source of the short message?

Let him check it, as long as he doesn't use his ID card when handling the card. What the school threatened you was just a scam, not that serious. It's not the college entrance examination! But if you really make a fortune, be frank and lenient. Resist strictly. People who never make mistakes, right?

Do you think the teacher will go to the telecommunications bureau to investigate for a cheat? He is not from the Public Security Bureau.

That's your communication secret. If he wants to check, he needs to show some certificates, such as law enforcement officers of the Public Security Bureau. At present, there is no special provision in this respect in national laws, so he won't do anything to you. Most oral education.

Then again, since you are the starting point of the answer, you should take it as the end point. So you should confess, and don't hurt everyone because of you. Be humane. As for whether the school will expel you. I don't think it's possible. I will definitely warn you at the first time. I won't say that I won't give you a chance to correct your mistakes.