The body of Fitri, 34, from Medan, Indonesia, was discovered by Amir's son in the living room when he came home about 7pm.
The injuries on Fitri's head indicated a blunt object was used to attack her.
There were indications that the assailant may have been known to the victim.
Fitri had worked for the family for the past six years.
There were signs that the intruders had tried to enter the locked master bedroom.
Fitri's valuables were missing.
City CID chief SAC II Ku Chin Wah said police believed there had been a struggle before the maid was killed. Police have not made any arrests yet.
