"She was actually talking to her sister, we're pretty certain she was involved in a conversation with her sister, who is overseas, at the time of the attack", Detective Inspector Andrew Stamper confirmed in a press conference on Thursday. All the time she think positive, she happy.
Police said they were confident of finding the perpetrator.
"Every woman in Australia - every person in Australia - should be able to travel home in safety".
Police appealed to the public for help tracking down the killer of 21-year-old Aiia Maasarwe, whose body was found yesterday near the campus of the Melbourne university where she was studying.
Aiia Maasarwe was taking a tram home in Melbourne after a comedy show late Wednesday while on the phone.
Those attending the vigil on the steps of the parliament were asked to wear black and to bring flowers, particularly red roses, which would be taken along the No.86 tram to Bundoora at 8pm.
"I have many dreams to be with her but I can not now".
Ms Maasarwe's uncle Abed Kittaneh told SBS Arabic24 that the news of her death came as a "bolt of lightning" for the family. "And despite that, we get this incredibly painful news", he said.
Aiia Maasarwe's father Saeed Maasarwe at the vigil for his daughter on the steps of Parliament House, Melbourne.
Maasarwe was studying Chinese and English in Shanghai. "She travelled all over the world".
Vice-chancellor John Dewar addressed the emotional crowds, announcing that security for students would be ramped up.
One of the organisers of Friday night's vigil, Jessamy Gleeson, said there was a lot of anger in the community that such an event was needed again.
"All I will say is, this was a horrific attack. Its weight is intolerable".
Campaigners on Friday called for an end to the "epidemic of violence against women" ahead of a vigil in memory Maasarwe.
"There was a real heaviness to the silence", organiser Megan Bridger-Darling said.
Det Insp Stamper added there was an "active line of inquiry" into whether she was "seriously assaulted" but would not divulge details, out of respect for her family.
"One of the reasons I like this area is that it's always so busy", Lowe said.