ISIS recruiters are preying on vulnerable domestic workers in Hong Kong and Singapore

A house maid cleans an apartment window in Jakarta while a construction site for high rise commercial and residential buildings are seen in the background.

(CNN)For six days a week, the three women worked as domestic workers in homes across Singapore. But in their spare time, they promoted ISIS online, donated money to militants overseas, and became so radicalized that at least one was ready to die as a suicide bomber in Syria, according to Singapore's Ministry of Home Affairs.

The women -- all Indonesian nationals -- were arrested in September under Singapore's Internal Security Act on suspicion of taking part in terror financing activities.
A spokeswoman for the Indonesian Embassy in Singapore confirmed the arrests and said it was providing consular assistance to the women, who do not have legal representation because they are still under investigation.
    The women were charged in court on October 23 with the financing of terrorism, according to the Singapore Ministry of Home Affairs. They face up to 10 years in prison and fines of up to $500,000 Singapore dollars ($362,000).
    Terrorism experts say they are not the only domestic workers who are believed to have been radicalized online while working in big Asian cities like Singapore and Hong Kong.
    As ISIS shifts its gaze towards Asia following the fall of its caliphate in the Middle East, these women are increasingly being targeted, albeit in a less organized way, experts warn.
    "They are preyed upon and exploited by militant cells who essentially view them as cash cows," said Nava Nuraniyah, a researcher at the Institute for Policy Analysis of Conflict (IPAC), an Indonesian think tank. "They have a stable income, speak English and usually have a broad international network, making them ideal (targets)."

    A radical fringe

    Such women represent a tiny subset of the approximately 250,000 domestic migrant workers who live in Singapore and of the 385,000 who reside in Hong Kong.
    "The vast majority of foreign workers are law-abiding and make a positive contribution to our society," said a spokesman for Singapore's Ministry of Home Affairs. "However, there are still individuals who continue to be radicalized by ISIS' violent ideology."
    Most of the cases identified so far involve Indonesian nationals, according to terrorism experts.
    CNN attempted to contact the three Indonesian women being held in Singapore but was unable to secure a comment.
    Between 2015 and 2017, IPAC conducted its own investigation into the radicalization of domestic workers and found there was a "radical fringe" of at least 50 Indonesian women working overseas as nannies, maids or caretakers for the elderly. Among these, 43 were based in Hong Kong, four in Singapore and three in Taiwan. Due to the difficulty of obtaining first-hand data and testimonies, these are the most recent figures available.
    According to a source in Indonesia with knowledge of the profiles of radicalized militants who were returned to their home country, at least 20 radicalized domestic workers were deported back to Indonesia, a country which has the largest population of Muslims in the world, including three who are currently undergoing a deradicalization program run in cooperation with the government.