A woman was detained Wednesday in connection with the suspected killing of North Korean leader Kim Jong Un’s half-brother, police said.

A man believed to be Kim Jong Nam died after falling ill at Kuala Lumpur’s airport on Tuesday. South Korean officials believe he was approached by two women and then poisoned as he waited to board a flight.

The woman arrested Wednesday was carrying a Vietnamese passport identifying her as 28-year-old Doan Thi Huong, according to a statement by the Royal Malaysia Police.

She was identified from security footage and was alone when she was arrested, the statement added.