Police are appealing for witnesses to come forward.
At around 5pm on Friday (13 August) a man was reportedly overheard in Earl Shilton before boarding the 48L bus.
The bus travelled along the A47 Hinckley Road before officers stopped the bus in Leicester Forest East.
A 49-year-old man from Sheffield was arrested on suspicion of making threats to kill and later released under investigation.
He was wearing a brown gown, black woolly hat and a dark jacket.
PC Baker said: “This was a very concerning incident for those who overheard these remarks.
“We would like to hear from anyone who saw the man described or from anyone who was travelling on the 48L bus at the time.”
Anyone with information is asked to call 101 quoting 21*455729.
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