He was driving his silver Mazda Lantis car (WG5108), which was found abandoned in Dalton Street in the suburb of Kaiti about 11am the following morning.
Officer in charge of the inquiry Detective Sergeant Kevin Ford says police believe Mr Singh is dead.
"Our long-term aim is to find his body and return it to his family."
Police believed people in the community knew what has happened to him.
"We appeal to them to come forward."
The team of ESR scientists assisting the investigation yesterday examined the car Mr Singh owned, in the hunt for clues that will assist with the inquiry.
Det Sgt Ford would not comment on the result of that examination at this stage.
"We have also got some out-of-town detectives here to help."
Investigators are still particularly interested in confirming the movements of Mr Singh's car over the 12-hour period before it was found in Dalton Street.
"It was found in an empty section in the street, about half way down the street," says Det Sgt Ford.
Police earlier this week revealed that Mr Singh's bank accounts had not been touched since his disappearance.
Mr Singh's family in India and friends in Gisborne have all expressed deepening concern for his safety and wellbeing, as have police.
His disappearance is a common talking point in the community, with many people expressing concern that someone could go missing for such a length of time in Gisborne.
"What has happened to him?" a local resident said this morning. "It's such a worry that someone could just vanish here.
"Someone must know where he is." .
Det Sgt Ford says police want to know where he went and who he was with on the night of December 29.
"It is known he left home alone at 11pm that night.
"We believe he went to either the BW campground area or the Rhythm and Vines music festival, but we are not sure."
Mr Singh was a field worker for a contracting company that does a range of work in the Poverty Bay area.
He had been in Gisborne since September last year.
Anyone with information that can assist the homicide inquiry is asked to contact Det Sgt Ford at Gisborne police station, phone 06 869 0200.
- The Gisborne Herald