Several bus passengers were threatened with a meat cleaver in south London, police said.
Scotland Yard are appealing for information after a man chased another passenger from a bus after being challenged about not paying his bus fare.
The incident took place on the Route 2 bus on Upper Tulse Hill, Brixton, on August 9 at 6.50am.
Less than an hour later the same man threatened a number of people at a bus stop in Elephant and Castle.
Officers said the man also made a homophobic comment before boarding a Route 196 bus.
Police are appealing for help tracing a man who was captured on CCTV.
Anyone with information is asked to call the Roads and Transport Policing Command via 101 quoting reference Cad 2611/09Aug.
If you wish to report anonymously please call Crimestoppers on 0800 555 111 or report online.