SINGAPORE - Security guard Sophia Shoba Ram Blas has been calling the Ministry of Foreign Affairs every other day since January.
The 49-year-old is hoping for good news about her sister.
Since her sister Rachel Liliwat Ram Blas, 55, left Singapore with her husband in 2010, there has been absolutely no word.
Ms Sophia believes that Madam Rachel is in Nigeria with her husband Felix Ibitayo.
"My other sister and I just want to find out how she is doing and if she is fine," she said, adding that the three girls had been close when they were growing up. "It isn't like her to have not got in touch for so long."
The sisters have been leading separate lives for some time now and may not have kept in contact much, but Ms Sophia started worrying last year.
She said: "I started having recurring bad dreams last December of Rachel asking for help. Call me superstitious, but it seemed like a bad omen."
She tried calling her sister, but the phone number did not work.
She then tried searching for Madam Rachel, who got married in 2000, at her old home.
"A Malay family now lives there," she said.
"The makcik (Malay for auntie) said that my sister's husband used to drop by in the first few months himself to collect letters... but she said she never saw my sister during those times."
Further checks made by the two sisters found that while Madam Rachel had taken out most of her savings, the remainder has been untouched since 2010.
Ms Sophia eventually went to the Immigration & Checkpoints Authority of Singapore, who told her that her sibling left Singapore in 2010.