German police have said they are considering disciplinary proceedings against an officer who failed to step in when an Adolf Hitler lookalike showed up at a motorbike meeting in the eastern state of Saxony.

State police said the incident is being investigated because the man dressed as the Nazi leader – sitting in a Wehrmacht-style sidecar – may have broken German laws on the use of illegal symbols.

A video posted on social media shows laughing bystanders, including an officer in a police van, photographing the biker and his pencil-moustached passenger.

In a post on Twitter, Saxony’s governor Michael Kretschmer said “the appearance as a mass murderer is more than tasteless”.

Mr Kretschmer said he hoped the biker meeting in Augustusburg, near the eastern city of Chemnitz, would take place again next year but that “first it needs to be clear: such behaviour is unacceptable and won’t happen again”.

Authorities in Saxony have struggled to combat the state’s image as a hive of neo-Nazi activity.

The far-right Alternative for Germany party received more than a quarter of the vote in state elections there last year.