KUALA LUMPUR, Malaysia >> One day after Malaysia revealed that VX nerve agent was used in a bizarre killing at the Kuala Lumpur airport, police said today that they have raided a condominium and were awaiting lab results on what they found.

The public poisoning of Kim Jong Nam, which took place amid crowds of travelers in a budget airport terminal, has boosted speculation that North Korea dispatched two killers to take out an outcast member of the ruling family. Kim’s younger half brother is Kim Jong Un, the ruler of North Korea.

Though Kim Jong Nam was not an obvious political threat to his sibling, he may have been seen as a potential rival in the country’s dynastic dictatorship.

Malaysia hasn’t directly accused the North Korean government of being behind the attack, but officials have said four North Korean men provided two women, an Indonesian and a Vietnamese, with poison. The four fled Malaysia shortly after the killing.

Today, police confirmed a raid earlier this week on the outskirts of Kuala Lumpur was part of the investigation. Senior police official Abdul Samah Mat, who is handling the investigation, did not specify what authorities found there, but said the items were being tested for traces of any chemicals.

Kim Jong Nam, who had been living abroad for years, was approached by the two women on Feb. 13 as he waited for a flight home to Macau. In grainy surveillance footage, the women appear to rub something onto his face before walking away in separate directions.

Malaysian police said they had been trained to go immediately to the washroom and clean their hands.

Both women seen in the video are in custody.

The oily poison was almost certainly produced in a sophisticated state weapons laboratory, experts say, and is banned under international treaties. North Korea never signed that treaty, and has spent decades developing a complex chemical weapons program that has long worried the international community.

VX is an extremely powerful poison, with an amount no larger than a few grains of salt enough to kill. An odorless chemical, it can be inhaled, swallowed or absorbed through the skin. Then, in anywhere from a few seconds to a few hours, it can cause a range of symptoms, from blurred vision to a headache. Enough exposure leads to convulsions, paralysis, respiratory failure and death.

It has the consistency of motor oil and can take days or even weeks to evaporate. It could have contaminated anywhere Kim was afterward, including medical facilities and the ambulance he was transported in, experts say.

Airport officials and police have insisted the facility is safe. Abdul Samah, the police official, said police are tracing the suspects’ steps to ensure public safety.

Asked if the airport cleanup had started, he said: “It is already in process.”