Once upon a time that regulator was 'the press'. This is the sort of area where independent media support functional democracies.

The engineer goes to a reporter. The reporter keeps the engineer's identify secret. If and when the police get serious about a prosecution, the engineer can then identify himself to authorities. Should the authorities decide not to investigate after reading the media reports (a very common situation) then the engineer's identity remain a secret held by the reporter.

But this all breaks down these days when authorities simply shout 'fake news' and ignore media reports.