An autopsy at Kuala Lumpur Hospital's forensics department was completed by yesterday evening, Selangor Police Chief Abdul Samah Mat said, but no results had yet been issued. The suspect was positively identified from closed-circuit television footage and was alone at the time, he said.
Yonhap News, citing a South Korean government source, also reported Mr Kim had been killed. Kim Jong Nam told medical workers before his death someone had touched his face from behind and attacked him with a chemical spray. A North Korean spy jailed by South Korea in 2012 is said to have admitted trying to organise a hit-and-run accident targeting him.
One woman is due to appear in court on Thursday, and a second woman has now been arrested, police say.
South Korea warned previous year of possible North Korean assassination attempts in its territory.
The shirt was listed online as "North Korea female who assassinated Kim Jong nam's T-shirt".
He lived in Pyongyang after finishing his overseas studies and was put in charge of overseeing North Korea's information technology policy.
"It also said: 'We have nowhere to go". Maureen Jeyasooriar contributed reporting from Kuala Lumpur.
According to two senior Malaysian government officials, who spoke on condition of anonymity because the case involves sensitive diplomacy, the elder Kim died en route to a hospital on Monday after suddenly falling ill at the airport's budget terminal.
As the elder brother, Kim Jong-nam was once considered heir apparent to the leadership, but he fell out of favour in 2001 after he tried to enter Japan with a fake passport, saying he wanted to visit Disneyland.More news: Previewing the Essex Vase greyhound racing extravaganza
Kim Jong Nam, as the eldest son in the family, had always been expected to rule North Korea after Kim Jong Il's death, backed by the Communist Party seniors including Jang Sung Taek.
Kim Jong-nam was born from his father's non-marital relationship with Sung Hae-rim, a South Korean-born actress who died in Moscow. He is believed to have been born May 10, 1971. Kim Jong-un is still just a nominal figure and the members of the power elite will be the ones in actual power. With the new US administration talking tough on Pyongyang, Kim Jong Un might have eliminated his half brother to prevent a possible ouster backed by China.
The news of Kim Jong Nam's death broke two days after Pyongyang conducted its first ballistic missile test of 2017.
It comes following the arrest of a second woman suspected of spraying a poisonous liquid into the face of Mr Kim in Kuala Lumpur worldwide airport on Monday as he prepared to board a flight to Macau, where he was living in exile. Pyongyang's nuclear and missile development is not only a message to the USA, but to China as well.
Who might have killed Kim? It's unclear what positon he has in the North Korean government.
North Korea is speculated to have been behind the attack, though there has not been any official confirmation.