"Mr Singh has got a number of wounds so there's definitely an indication of a violent struggle in or around the vehicle," Mr Lynch said.
Police were unable to interview his 31-year-old partner last night because she was in such a "distressed state". They did manage to get some details from her last night but she could tell them only that the killer was a man.
Up to 20 detectives were working on the scene today, combing the area for evidence.
The scene examination included the area around Norman Spencer Drive and the couple's car.
An item of interest, a personal belonging of Mr Singh's was located in nearby Kenderdine Road.
Police were still searching for a sharp object believed to have been used in Mr Singh's murder.
Mr Lynch said police had retrieved CCTV footage from a nearby business which had enabled the investigation team to narrow down timeframes.
"Police can confirm that Mr Singh and his partner stopped outside the Manukau Events Centre in their vehicle at approximately 7.20pm on Thursday evening. It is evident that at the time Mr Singh was murdered, a large number of vehicles including a number of buses passed the vehicle.
"Motorists passing by may recall seeing Mr Singh's silver Honda motor vehicle that can be seen with its indicator flashing. Police are particularly interested in further information on another vehicle that was parked behind Mr Singh's which left the scene prior to police arrival," Mr Lynch said.
"We ask that anyone who drove down Norman Spencer Drive between 7.20pm and 7.45pm on Thursday night and might have seen Mr Singh's car parked outside the Manukau Events Centre please come forward to Police," he said.
"Additionally we would like to know more about the car that is seen parked behind Mr Singh's vehicle."
Counties Manukau Police could be contacted on 09 261 1300 or information could be given anonymously through Crimestoppers on 0800 555 111.
Up to 20 detectives were working on the scene today, combing the area for evidence.
Mr Lynch said they were also interested in hearing from businesses on Norman Spencer Drive who had CCTV.