An Ethiopian man in Kenya was sentenced to four months in prison on Thursday for joking about a bomb after boarding a Kenya Airways flight, the BBC has learned.

Chifraye Bekele’s joke led to the cancellation of the Johannesburg-bound flight in April and to a three-hour shutdown of Jomo Kenyatta International Airport (JKIA) in the capital, Nairobi.

Magistrate Christine Njagi found him guilty of “imperilling the safety of aircraft and persons on board”.

According to the judgement, passed on to the BBC, Bekele had said to a flight attendant as she was closing an overhead locker: “Why are you scared? You think it’s a bomb?”

The flight attendant consulted her colleagues and also informed the captain, who decided to taxi back for the plane to be searched.

All the passengers had to disembark, resulting in the cancellation of the flight.

Bekele was taken into custody and has been in prison since then.

In court, testifying via a translator, he said he did not make the joke as he only spoke Amharic and not English.

But the magistrate sentenced him to four months in jail or a 100,000 Kenyan shillings ($1,000; £800) fine.

At the moment he cannot pay the fine, so remains in prison.

He is not the only traveller to have found a joke that crossed a line.

A British student nearly faced up to 15 years in jail in the US in 2004 for joking that she was carrying bombs – she was allowed to return home after agreeing to donate $1,000 to a 9/11 victims’ fund and write a letter of apology.

In 2013 a man was briefly detained at JFK International Airport in New York after being overheard using the word “bomb” to a friend. It turned out he was just talking about a sandwich, known as “The Bomb”.