Malaysian police said Wednesday they have arrested one of the two women suspected of killing Kim Jong Nam, the estranged half brother of North Korea’s leader Kim Jong Un, who was killed Monday. Kim Jong Nam was attacked in a shopping area at Kuala Lumpur airport as he waited to board a flight to Macau. He died on his way to hospital.

South Korea has pointed the finger of blame at Pyongyang, with the country’s spy agency saying that two female assassins were responsible for killing the 45-year-old exile. Malaysian authorities said one of the suspects was arrested at Kuala Lumpur airport on Wednesday while carrying a Vietnamese passport identifying her as as Doan Thi Huong – born May 31, 1988. The Malaysian authorities are working with North Korean and Vietnamese officials to confirm the woman’s identity.

The woman was “positively identified from the CCTV footage at the airport and was alone at the time of arrest,” the police said in a statement. Earlier on Wednesday a local newspaper, the Malay Mail, published a photograph claiming to show one of the suspects. The picture shows a woman with short black hair wearing a white top with the letters “LOL” printed across the front.

The police are continuing to search for the second female suspect, as well as up to four men who may have been involved in the murder. The body was transferred to another hospital on Wednesday where an autopsy will be conducted. A North Korean embassy car was seen at the hospital.

The exact details of just how Kim Jong Nam was killed are still unclear, though all reports suggest he was poisoned. According to Selangor state’s criminal investigation chief Fadzil Ahmat, who spoke to Malaysia’s Star newspaper, Kim Jong Nam “told the receptionist at the departure hall that someone had grabbed his face from behind and splashed some liquid on him.” It was also reported Tuesday that poisoned needles had been used in the attack.

The South Korea spy agency said it suspects that North Korea, and specifically Kim Jong Un, of being behind the assassination.

“If the murder of Kim Jong Nam was confirmed to be committed by the North Korean regime, that would clearly depict the brutality and inhumanity of the Kim Jong Un regime,” South Korean Prime Minister Hwang Kyo-ahn — also the country’s acting president — told a security council meeting.

South Korea’s National Intelligence Service believes there has been a long-standing order in place to kill Nam. In 2012, Nam was the subject of another assassination attempt, when a North Korean spy admitted planning to target him in a hit-and-run attack.