Prabha Arun Kumar, who was sent to Australia on a three-year deputation by MindTree company, was stabbed to death by an unidentified assailant while walking towards her home in Sydney in March.
Over 2,000 people have been questioned by police and almost 250 statements have been recorded as part of the investigation into the killing, the Sydney Morning Herald reported.
Police have several persons of interest in their sights over the killing of the mother of one as they attempt to piece together who stabbed the IT worker after she got off the train at Parramatta on March 7 last year.
"We have considered the possibility that an offender had (helped commit or been involved with)this crime outside of Australia," Detective Sergeant Ritchie Sim told Fairfax Media.
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While detectives weigh up the theory that someone in a country 10,000 kilometres away had a hand in her death, they are confident Kumar did not know the person who actually ended her life.
"We are considering the possibility that the offender is still in Australia as well as the possibility the offender has left Australia," he said.
Kumar, whowas speaking to her India-based husband Arun Kumar on the phonewhile walking down a dimly lit path in a Paramatta park,wasbarely 300 metres awayfrom her home in western Sydney when shewas "suddenly" approached by someone and fatally stabbed in the neck.
Over last one year, investigators' probe has spanned to both countries.
There were crucial missingminutes between when Kumar turned onto an area that wasnot covered byCCTV, thatposeda challenge in the probe.
Investigators said that there were aspects of Kumar's life that need to be explored further. Theyhave ruled out sexual assault and robbery are motives in the murder.
They are said to bein close contact with authorities in India, where Kumar and the rest of her family live.
"Because Prabha was an Indian National, the geographical distance between our two countries is an obstacle,"Sim said.