Before her body was found, a Facebook Group called "Help find Preethi Reddy" had been set up by the family to assist the investigation. The investigation officials also said that the main suspect in the killing, her former boyfriend, died in a road accident that seemed deliberate, shortly after she was murdered.
She bought two bottles of water before leaving, walking south towards Market Street, where police said Reddy was staying at a hotel with a man known to her.
The last images police have of Dr Reddy showed her at McDonald's on George Street in Sydney's CBD at around 2.15am on Sunday.
After her family filed a missing person case at the police station, investigators launched a search for her auto which they found parked near Strachan Street, Kingsford, about 9.30 pm on Tuesday.
Police officers searched the auto after it was found at Strachan Lane.
Det Supt Dengate said police spoke with the man before he died in a "deliberate" head-on collision on the New England Highway at Willow Tree, in the Upper Hunter, about 10pm on Monday.
Dr Reddy told Narde she had "moved on" and meant to "start a new life" with her new boyfriend, according to a police source. After the cops declared tracing the mortal remains of Preethi, Nithya posted on the page, "Our dearest Preethi is no longer with us". Thank you all for your kind messages and from the bottom of my heart and support in looking for her.
Reddy's body which was stabbed numerous times was found in a vehicle parked in Strachan Lane in Kingsford on Tuesday, days after she went missing from Sydney's busiest area under mysterious circumstances.
"Glenbrook Dental Surgery staff are in mourning to hear the sad news about Preethi Reddy", the post read.
ABC identified Preethi's ex-boyfriend as Harsh Narde. The 49-year-old male truck driver managed to escape before the entire truck was engulfed in flames.
She last spoke with her family that morning, saying she planned to head home after having a late breakfast.
A colleague of Dr Reddy and Narde's, who attended the conference, said he last saw the pair chatting animatedly in the hotel lobby following the event.