A new theory has emerged about the motive behind an alleged triple murder.

It comes as the manhunt for accused killer Julian Ingram continues in central west New South Wales.

Police allege Ingram shot dead his heavily pregnant ex, 25-year-old Sophie Quinn and her friend John Harris, 32, while they were in the back of Quinn’s black Suzuki Swift on Bokhara St in Lake Cargelligo on January 22.

He then allegedly drove several minutes to Walker St where he is accused of opening fire and killing Quinn’s aunty Nerida Quinn, 50, in the driveway of a Walker St home.

A friend of the 50-year-old victim’s son, 19-year-old Kaleb Macqueen, was also seriously injured in the alleged attack.

Macqueen alleged Ingram was laughing as he fired the shots.

Locals believe Ingram recently learnt he was not the father of his ex-partner’s unborn child, which may have triggered the alleged killing spree.

Ingram has been on the run since the alleged murders, and the manhunt remains focused on remote country around Mount Hope, about an hour northwest of Lake Cargelligo.

Officers are battling extreme heat and using aerial sweeps to conduct what police are calling a large-scale search.

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The operation is not expected to be scaled back any time soon, as authorities continue their efforts to locate the accused triple murderer.

Overnight, police released fresh photos of the ute they believe Ingram used to flee Lake Cargelligo after the shootings. The images are the clearest yet of the getaway car and are expected to be a key focus of the investigation.

Police are urging anyone who may have spotted the car or Ingram to come forward immediately.