Doan Thi Huong gained notoriety last week after Malaysian police shared CCTV images of the 28-year-old at a Kuala Lumpur airport - wearing a top emblazoned with "LOL" - shortly after the Feb 13 assassination of Kim Jong Nam.

She was arrested alongside an Indonesian woman, both accused of carrying out a fatal poison attack on the unsuspecting Kim ahead of his flight home to Macau.

The unlikely connection between a country girl from a poor rural backwater 150km outside Hanoi to a high-profile assassination, has added another layer of intrigue to a crime that has captivated with its echoes of Cold War-era conspiracy and spycraft.

Houng's arrest has caused fevered interest inside Vietnam, despite attempts by security officials in the communist nation to control the information flow.

Her family recall a girl who broke the conservative conventions of Quan Phuong village with her dyed hair, edgy clothes and foreign boyfriends since she left aged 18 apparently to study.

"At first we doubted it was her when we saw the picture with the 'LOL' shirt," stepmother Nguyen Thi Vy told AFP.

"But when someone bought a clearer picture here, we knew it was our Huong," she said.

"If she committed the crime, she has to suffer, we can't do anything... but I think she must have been set up by someone."

Malaysia's police chief has scotched suggestions Huong and the other female suspect were duped.

On Wednesday, he said CCTV footage showed they were "very aware" the substance they wiped on Kim's face was toxic, adding the pair had practised.

But when she returned home during the Tet lunar new year festival in late January she gave no hint of being mixed up in serious criminality, locals said.

Neighbour Maria Nguyen described Huong as someone who stood out in the small village of dozens of homes encircled by paddy fields.

"She has always been very fashionable, with colorful hair," she said. "Every Tet she would come back home with some different (foreign) man," she added.

Vietnamese social media has filled gaps in Huong's history with conjecture and rumours.

Unsubstantiated photographs are doing the rounds of a woman who looks similar to Huong auditioning for a television talent show.

Others have linked to a YouTube channel apparently showing the same young woman kissing a famous social media prankster.

They have fuelled the mystery surrounding a girl caught in the eye of a scandal involving North Korea, a secretive state with a long track record of carrying out assassinations and kidnappings overseas.

Huong was last seen by her family just a few weeks ago during Tet, arriving broke and leaving after a few days.

"She did not have a penny in her pocket. I gave her some money to buy a bus ticket," her stepmother added.

Huong's brother Doan Van Binh said he knew little about his sister's life after she left the village.

"I encouraged her to study and earn money so that her future would be good," he said.

"My family is very sad. We all thought she was in a good place," he added.

Agence France Presse - February 23, 2017