A second female suspect was arrested early Thursday morning.
The Royal Malaysian Police confirmed that a 25 year-old woman was detained at 2 a.m. carrying an Indonesian passport.
She was said to have been identified from CCTV footage at Kuala Lumpur International Airport, the scene of the crime.
This came a day after the first arrest on Wednesday of a 28-year old woman with a Vietnamese passport.
They are thought to be the two women who approached Kim at the airport Monday morning and poisoned him with some sort of needle or spray.
The authorities are working with both the Indonesian and Vietnamese embassies to confirm their identities.
News reports have emerged of a third, male suspect in custody, but no official statement has been made.
The police have said they are still looking for more suspects.
An autopsy on Kim's body was completed Wednesday night, but the results have yet to be released.
Malaysia's Deputy Prime Minister gave a statement on Thursday confirming that the victim was Kim Jong-nam.
The police up 'til this point had officially referred to him as "Kim Chol," which was the name found on the passport he was carrying.
The Deputy Prime Minister has also promised that the body will be returned to the next of kin or the North Korean embassy in Kuala Lumpur once all medical examinations have been completed.
Officials from the North Korean embassy in Kuala Lumpur had insisted that the body be handed over before the autopsy took place but the request was denied.
This has raised further suspicions of foul play from Pyongyang.
South Korea's National Intelligence Service claimed Kim had been targeted by the North Korean leadership for several years.
"The South Korean government has said they are communicating with their Malaysian counterparts, but with no diplomatic authority in this matter, they are having to play the waiting game as the investigation continues.
Still, if it is discovered Pyongyang was involved in the murder, they have promised to rally international pressure on the regime.
Kwon Jang-ho, Arirang News."
According to Malaysia's police inspector General, a third suspect is arrested.
The 26-year-old man Muhammad Farid Bin Jalaluddin, identified as the boyfriend of the Indonesian woman arrested earlier on Thursday.