UPDATE 10.20pm: POLICE are trying to defuse a bomb strapped to a teenage girl at a multimillion dollar house in the exclusive Sydney suburb of Mosman.
The investigation into the incident on Sydney's lower north shore is now being headed by the robbery and serious crimes squad, which also deals with extortion attempts.
NSW Assistant Police Commissioner Mark Murdoch did not confirm whether the 18-year-old girl was a victim of an extortion attempt - instead he said police were still unsure what they were dealing with.
"We don't know what we are dealing with...we are working very hard to find out exactly what it is, and equally important, what it isn't," Mr Murdoch said tonight.
He said the girl, believed to be a Year 12 student at a north shore private school, was extremely calm, with specialist officers helping to guide her through the ordeal.
