[mothered]

He's returned to work full-time.

On the grounds of the following, I don't understand how he's returned to normal duties:

He's already getting Investigated by school/police for other cases. He's only just been placed on suspended leave with pay.

An Investigation can take a significant amount of time and resources to conclude. The latter part of your post In the above quote, was only 4 weeks ago.

No idea what happened or how it went but he seems to be back in teaching.

Perhaps not many people came forward, and/or the evidence provided was not sufficient to warrant an arrest.

Whatever the reason, It's not right.