Opinion please ,

Today after school DS said he had to move his clip this morning because one of his friend was saying " i'm a dummy " , then the teacher asked who said that ?

Another student ( who always gets on DS' nerves ) accused DS for saying that . DS then raised his voice and said " it wasn't me ! it was student A "

The boy who said it didn't admit it . DS was really mad being accused on something he didn't do , but he had to move his clip because he was raising his voice to his classmate .

I feel like DS did have a reason for raising his voice because he was accused on something he didn't do , and he felt it was very unfair that he had to move his clip for defending himself . I know DS will tell you the truth , if he does it , then he'll tell you he did it .

Should i just let this go or should i send his teacher an email ? On the way home , DS said , when his teacher made him move his clip that's when he really feels like he hates her for being so unfair to him . What bothers me the most is that he's being accused on something he didn't do and of course he's not happy about it .