Malaysian police investigating the killing of the North Korean leader’s half-brother held one woman in custody Wednesday and searched for other possible suspects a day after the apparent lethal poisoning in a busy airport terminal.

The detention of a potential female plotter fit with Malaysian reports Tuesday saying a woman ambushed Kim Jong Nam at Kuala Lumpur’s international airport with a cloth soaked in some kind of deadly liquid.

North Korea’s tightly controlled state media has not made reference to the death of the 45-year-old Kim, who was estranged from the North’s leader Kim Jung Un and had lived outside the country for more than a decade.

But the opaqueness in North Korea also opens room for speculation about the motives behind the killing and whether it could be traced back to high-level decisions in Pyongyang.

Just three years ago, Kim Jong Un had his uncle — and Kim Jong Nam’s mentor — executed on suspicion of building an alternate power base. Meanwhile, a slew of high-profile defections have raised questions about the stability of the regime.