UPDATE: A Gold Coast mother has been charged with murdering her disabled son and daughter to allegedly pocket their insurance claims.
The 51-year-old is accused of staging her 18-year-old daughter's suicide in 2012, before doing the same thing with her 26-year-old in July last year.
Police also allege she tortured her 25-year-old daughter.
EARLIER: A woman has been arrested following the deaths of an 18-year-old woman and a 26-year-old man, who died between September 2012 and July last year.
Police believe their deaths are suspicious.
Detectives from the Gold Coast Criminal Investigation Branch and the Homicide Investigation Unit worked together to make the arrest.
They haven't released any further details at this stage but are expecting to hold a media conference at police headquarters in Brisbane later today.