KUALA LUMPUR - Malaysian police arrested a third suspect for questioning in connection with the death of Kim Jong Nam, the estranged half-brother of North Korean leader Kim Jong Un, an official said on Thursday (Feb 16).

The latest suspect arrested was a 26-year-old Malaysian male, believed to be the boyfriend of a second female suspect who was arrested in the wee hours of Thursday morning in relation to Mr Kim's death.

Police said the court had issued a seven-day remand for her and another woman holding a Vietnamese passport who was arrested a day earlier.

"The third suspect is still being questioned to find out how much he knows about his girlfriend's activities," Selangor state police chief Datuk Abdul Samah told The Straits Times.

A statement issued by police on Thursday evening named the suspect as Muhammad Farid Bin Jalaluddin. The statement said he was arrested on Wednesday evening and is "currently remanded in custody to assist investigation".

South Korean lawmakers, citing the country's spy agency, have said it suspects that Mr Kim was attacked by two female agents of North Korea at the Kuala Lumpur International Airport 2 (KLIA2) on Monday morning as he was readying to board a flight to Macau, where he had spent many years in exile.

The assassins reportedly sprayed toxins in Mr Kim's face.

The police identified the second woman as a 25-year-old who holds an Indonesian passport. The woman's passport identifies her as Siti Aishah, according to a statement issued by Malaysia police. It said she's from Serang, west of Java island.

"She was also positively identified from the CCTV footage at the airport and was alone at the time of arrest," Inspector-General of Police Khalid Abu Bakar said in the statement.

Indonesia's Foreign Ministry on Thursday confirmed the arrest of a female national and said it had requested consular access to the woman to provide legal assistance.

The first detained female suspect is a 28-year-old named as Doan Thi Huong. She was caught at KLIA2 on Wednesday morning attempting to depart to Vietnam.

Local dailies reported that the woman told officers she was roped in for a prank to spray liquid onto a stranger at the airport.

CCTV images that emerged in Malaysian media, purportedly of the first detained female suspect, showed an Asian woman wearing a white top with the letters "LOL" emblazoned on the front.

Authorities are still looking for more suspects at large.

The deceased was travelling with a passport identifying him as Kim Chol, 46, from Pyongyang, Malaysia police said.

Deputy Prime Minister Ahmad Zahid Hamidi told reporters on Thursday that the authorities have concluded that Kim Chol and Kim Jong Nam was the same person. Mr Kim was carrying documents with two different names, and the passport used was authentic, Datuk Seri Zahid said.

"He carries two different identities. Probably this is an undercover document," he said.

With regards to the repatriation of Mr Kim's body back to North Korea as the latter has requested, Mr Zahid added that Malaysia has to honour bilateral relations between countries, and that procedures will be followed.

Mr Kim's autopsy was completed on Wednesday evening, with authorities closely guarding the hospital mortuary to prevent unauthorised removal of the body. Officials have not released the post-mortem result.

Officials from the North Korean embassy was reported to have protested against the autopsy and stayed at the hospital for hours.

Malaysian police officers were seen paying a brief visit to the North's embassy in Kuala Lumpur on Thursday.

Meanwhile, the Chemistry Department said they had received for analysis several samples of a product as part of the police investigation into Mr Kim's death, Bernama reported. But the department did not say what type of product it was, or if it was a liquid or poison.

Malaysian authorities said Mr Kim, a portly 45-year-old with a playboy reputation, was walking through the departure hall outside the immigration area when he was attacked. He reportedly died on the way to hospital.