Okay, so you know how there are some people who work to make sure everyone follows the rules? That's kind of like what the Office of Police Integrity (OPI) does.
They are a group of grown-up helpers who make sure that police officers follow the rules and don't do anything wrong. They want to make sure that the police are doing their job the right way, being fair and not being mean to people.
Sometimes, people might worry that the police might not be doing the right things or breaking the rules. That's when the OPI steps in to check and make sure everything is okay. They look at the way police officers do their job and make suggestions on how they could do better.
So, just like there are grown-up helpers to make sure we all follow the rules, the Office of Police Integrity helps police officers follow the rules too!