0717 I was caught telling a lie

The commender asked me to realize what happened to the missing mouse.This morning I replied to her that  all our classmates were innocent.No one took the mouse,neither did anyone use a computer.Then she asked me some questions.Our  dialogues were as below.

She:Why you guys have a class in a computer room without using computers?
Me:Reading teacher has things to do so he exchange classes with Atonio.That is the reason we showed up in the computer room.
She:When it comes to Antonio...I have a question and you have to answer me honestly.
Me:Ok...
She:Does Antonio fail to show up at class often?
Me:Well,actually he never fails to show up at class.The reason makes you think Antonio skips the class often is that he has a one-to-one conversation in the other room.
She:However he did not have conversations with any of you last Friday.What's more,Edmund found a good excuse for him.Edmund said Antonio would show up in a few minutes,which turned out to be a lie.
Me:...