If, hypothetically, a member of the European parliament was caught on video offering to amend laws in exchange for cash, who would investigate such a thing?

The answer – rather less hypothetical after Britain’s Sunday Times exposed what appears like serious misconduct from four MEPs – depends on who you speak to.

The European Anti-Fraud Office, or OLAF, thinks it should be the one investigating. After all, what’s the point of having a dedicated EU anti-fraud agency if you can’t investigate credible allegations that MEPs are taking bribes?

But when an OLAF team showed up in the parliament to search the MEPs offices last week, they were unceremoniously denied entry by parliamentary authorities. Parliamentarians insisted OLAF was set up to investigate fraud against the EU budget, and it’s not clear that the EU has lost money in this episode.

OLAF disagrees on the limits of its role, but so far hasn’t been anywhere near the MEPs’ offices, which have been sealed off.

Insiders say part of the reason for the stand-off is a power struggle between parliament and the European Commission, the EU’s executive branch, which is ultimately OLAF’s master.