We refer to the letter Horror flight on board MH161 .

Malaysia Airlines regrets and views the matters raised by Mrs Radhika Iyer-O'Sullivan very seriously and we initiated an immediate investigation into the matter.

The results of our investigations show that the passenger who was given a seat next to Mrs Iyer-O'Sullivan was not allowed into Karachi in view of insufficient travel documents on arrival.

From an immigration standpoint, if a passenger fails to provide adequate documents, they can be turned away by the arrival country though airlines will still to treat the person as a passenger.

As such, he was not assigned to a separate seating area.

It is truly unfortunate that a Malaysian chose to behave in this manner, particularly on a flight filled with multi-ethnic passengers. In checking with our in-flight supervisor and crew, they themselves, too, were shocked by his behaviour.

The in-flight supervisor made a judgment call to provide Mrs Iyer-O'Sullivan with an alternative seat, instead of one for that passenger, because they needed to remove her from that environment.

This was aimed at ensuring that the crew could keep a closer eye on her, and to prevent any reoccurrence of the earlier incident.

Throughout the flight, our cabin crew kept a close watch on both passengers. During the constant rounds, the cabin crew was glad to note that Mrs Iyer-O'Sullivan was resting and they assumed that the rest of the journey went well.

On arrival, the male passenger was only allowed to leave the airplane after all the other passengers had disembarked. Our ground staff were on hand to meet him when the cabin crew handed over his travel documents.

We truly regret the incident and have offered Mrs Iyer-O'Sullivan service recovery beyond the norm. We are currently in discussions with her to reach a mutually agreeable solution.

The writer is manager, Customer Response, Malaysia Airlines.