article_snippet: Scroll down for video .
article_snippet: Passers-by captured the moment river patrol officers arrived on the scene having been alerted by passers-by . '
article_snippet: But I was also worried that if they did actually catch anything, then they could be terribly ill as the water here is very polluted.'
highlights_snippet: Passers-by in St Petersburg, Russia, became concerned and raised alarm .
  