SINGAPORE - A man linked to his sister's death may have his original assault charge upgraded to a more serious offence as prosecutors await the results of a post-mortem on the woman, Ms Huang Baoying, 19.

On Wednesday (May 19), a police prosecutor told District Judge Terence Tay that her cause of death has not been ascertained, adding that her brother, Huang Bocan, may face more charges, including wrongful confinement.

The 29-year-old is said to be one of three people who used a wooden pole to hit Ms Huang in a unit at Block 602 Clementi West Street 1 at around 11pm on May 4.

The Singaporean, who is represented by lawyers Josephus Tan and Cory Wong from Invictus Law Corporation, was charged in court on May 6 with one count of voluntarily causing grievous hurt to his sister.

His two alleged accomplices - Singapore permanent resident Chee Mei Wan, 41, and Singaporean Lim Peng Tiong, 62 - were each handed a similar charge about a week later.

According to the Inland Revenue Authority of Singapore's records, Lim is one of two owners of the flat where Ms Huang's body was found.

Court documents did not state the relationship between Lim, Chee and the teenager.

In an earlier statement, police said that they were alerted to the case at around 6.30am on May 5.

Officers arrived at the flat and found Ms Huang lying motionless inside. She was pronounced dead at the scene.

Her three alleged attackers are now remanded at the Central Police Division and their cases have been adjourned to May 25.

For voluntarily causing grievous hurt, an offender can be jailed for up to 10 years and fined or caned.

Chee cannot be caned as she is a woman.