Passengers aboard a South African Airways (SAA) flight between Johannesburg and Hong Kong were robbed mid-air of cash and jewelry while they were asleep Monday.

The incident came to light after some passengers informed the cabin crew that their valuables — stowed in the overhead compartments — had gone missing during the flight. However, the missing possessions mysteriously turned up on some of the cabin seats when the staff boarded the flight to clean the aircraft after it landed.

SAA spokesman Tlali Tlali confirmed the incident Thursday and said it happened on Flight SA 286 on Monday and two passengers approached the crew complaining they had lost their valuables.

“One of the complainants was able to point out a few passengers who had behaved in a suspicious manner in the cabin and who were seen opening some overhead compartments while other passengers were sleeping,” he said, Times Live reported.

The crew informed the authorities in Hong Kong and police boarded the aircraft when it landed.

“A call was made to have the police meet the aircraft on arrival. The rest of the passengers disembarked and the suspects identified were ordered to remain in the aircraft and were searched by the police in Hong Kong. Nothing was found on them during the search,” Tlali said.

He said the valuables were recovered by the cleaning staff as they cleaned the aircraft. The items were found on seats of the suspects and complainants. “The items were returned to the complainants‚" he said.

Tlali said SAA would not hesitate to impose a ban on any passengers “who are reported to have breached its conditions of carriage as they form part of the rights and responsibilities of the airline and its customers.” Not just SAA, many airlines that operate to or from Hong Kong have to struggle with this challenge, he continued.

“In matters where suspects are charged and successfully prosecuted, they get blacklisted and may not be able to book and fly on SAA again. In addition, we introduced enhanced cabin monitoring when flying at night or when the cabin has been dimmed to allow passengers to rest or sleep. This measure has significantly lowered incidents of this nature but it’s not foolproof,” he said, All 4 Women reported.

The suspects were not arrested as there was no evidence linking them directly to the theft.

In a similar incident in January this year, several passengers onboard a flight bound for Prague from Beijing were robbed by another passenger mid-air. Money was stolen from the luggage stored in the overhead compartments and also from seat pockets.

The cabin crew was alerted by one of the victims who discovered her money was missing half an hour before the flight was supposed to land. This prompted the co-passengers to check their luggage during which they discovered their cash was also robbed. Upon arrival, a Chinese was arrested on suspicion of theft, The Coverage reported.