Police have arrested a fourth person - a North Korean man to facilitate investigations into the death of Kim Jong-nam, the estranged elder half-brother of North Korean leader Kim Jong-un.

Inspector-General of Police Tan Sri Khalid Abu Bakar said the man was detained at 9.50pm yesterday.

In a statement today, he said an identity card (i-KAD) in the man's possession identified him as Ri Jong Chol, with May 6, 1970 and DPRK cited as his date and place of birth.

So far, two foreign women and a local man have been detained in connection with the case.

The first female suspect aged 27 who was arrested at KL International Airport 2 (klia2) at 8.20am on Wednesday (Feb 15), was in possession of a Vietnamese travel document.

Police on Thursday (Feb 16) detained a second female suspect who was in possession of an Indonesian passport; a Malaysian man believed to be her companion was nabbed a day earlier on Wednesday.

The suspects are on remand for seven days since Thursday.

Last Monday, it was reported that Jong-nam was at klia2 to board a flight to Macau when a woman suddenly covered his face with a cloth laced with what is believed to be poison.

Jong-nam sought help at a customer service counter at klia2 and was rushed to Putrajaya Hospital but died on the way. -- Bernama