The man who filmed a police officer threatening him after he swore at the constable says the threats were unacceptable and overstepped the boundaries.
John Martin, 24, was riding his bicycle on a footpath in Forrestfield on Tuesday about 2.30pm when a constable from the traffic enforcement group pulled him over.
The officer, whose actions are being investigated internally, issued an infringement to Mr Martin for failing to wear a helmet.
In the video the disgruntled man suggests the fine is a "joke" before asking "what crimes" the officer stopped. The officer walks away only to be told by the man to "catch you later, go stop some f...ing criminals".
The constable then walks up to the man and uses some colourful language of his own to suggest what may happen if he swears again, including being sexually assaulted in a jail cell.
Mr Martin uploaded the video, which was filmed on a mobile phone, on to Facebook shortly after the incident. The video attracted more than 22,000 likes and has since been reposted on video sharing site LiveLeak where it has received a further 45,000 hits.
WA Police Union president George Tilbury said officers interacted with the public 24 hours a day, seven days a week and on some of these occasions the situations could be quite frustrating.
Mr Martin's lawyer John Hammond said the context of his client being pulled over and later threatened was "fairly trivial" but no amount of justification would excuse the officer's behaviour. Mr Martin is planning to make a formal complaint about the incident.