Traces of blood found in the canopy of missing camper Russell Hill's car have been linked by DNA to his mistress Carol Clay.
The evidence was revealed at Victoria's Supreme Court on Thursday in the murder trial of Greg Lynn, who is accused of killing the elderly couple.
Lynn, 57, has pleaded not guilty to the murder of Mr Hill, 74, and Mrs Clay, 73, in the state's remote Wonnangatta Valley in March 2020.
He is accused of killing the pair while they were camping and then burning their remains in the bush months later.
Victoria Police forensic officer Mark Gellaty told the court he examined Mr Hill's Toyota LandCruiser for the "possible presence" of blood in February 2022.
These efforts discovered six small "apparent" blood stains and a "clear, jelly-like" fatty deposit.
Mr Gellaty said what was found "behaved like blood" and gave a DNA profile but this couldn't be officially confirmed.
However, further tests of both the stain and fatty deposit revealed "extremely strong support to that proposition" it belonged to Mrs Clay.
Mr Gellaty said further analysis of the blood stains indicated "there was some sort of forceful event in that vicinity" of the vehicle.
Defence barrister Dermot Dann previously told the jury a scuffle broke out at Bucks Camp after Mr Hill took a gun from Lynn's vehicle.
He claimed Mrs Clay was accidentally shot by Mr Hill and the older man then came at Lynn with a knife, and was accidentally stabbed in the chest as Lynn defended himself.
Prosecutors dispute those claims, alleging Lynn intentionally killed the couple after Mr Hill threatened to send drone footage to police of Lynn deer hunting near the camp.
Lynn admits later dumping and burning the couple's bodies at Union Spur in what Mr Dann has described as a "series of terrible choices".
