We’re used to seeing John Oliver tackle all sorts of serious issues each week on HBO’s Last Week Tonight, even though he does it in a unique humorous style. Each show has a serious matter that Oliver explains as simply, and as heartbreakingly hilariously as possible. This week’s serious segment concerns police accountability, and it’s one you also have to watch.

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Not all police officers make the news for questionable actions while on duty, whether it’s shooting incidents or brutality. And Oliver agrees that only a few bad apples exist inside police stations. But he also explains that it’s really hard for others to held those bad apples accountable for their actions, which makes police accountability practically impossible.

One of the disturbing details concerning police accountability is the absence of palpable data. Oliver even revisits a statement made by the FBI’s Director James Comey in 2015 regarding police oversight. He said at the time that he had no idea how many people were shot by police the previous month or year because such data simply doesn’t exist.

Oliver also explains that it’s difficult for prosecutors to investigate police officers who they work with, and reveals the loopholes that allow police officers to expunge data from their records after a certain time has passed. The report also shows that it’s relatively easy for a policeman who’s under investigation to continue to work, or to simply quit and get a job with a different police station to avoid an inquiry.

Oliver’s full segment on police accountability follows below.