Jamie Michael Tilley, 36, and Jack Davies, William Patrick Thomas and Mitchell James Bentley, all aged 27, have pleaded not guilty to kidnapping and murdering Brendan Vollmost, 23, at South Windsor in March 2015.

Giving evidence at a NSW Supreme Court trial on Tuesday, DNA expert Jeremy Watherston told the jury Mr Vollmost's blood was found on a steel baton taken from his shed as was the DNA of Thomas.

The baton was extendable with a foam handle. Mr Watherston said the blood was not visible to the human eye.

Mr Vollmost's blood was also found on a number of tools and elsewhere in the shed, the DNA expert said on Tuesday.

Under cross-examination from Thomas's lawyer, Nicole Carroll, Mr Watherston said he could not be certain when or how the DNA ended up on the baton.

Mr Watherston said he also found the DNA of a number of other individuals on the baton and at the crime scene.

The jury has seen CCTV footage from outside Mr Vollmost's home showing him running through a gate toward the backyard shed, followed by four men, before his body is carried out by two men.

He hasn't been seen since.

The Crown alleges the four men wanted to recover a drug debt and "obtain the gratification of demonstrating they were a group to be respected".

The men, who belonged to a group called the Blood Brothers and respectively had the nicknames Coach, Captain, Medium and Smallsie, also deny assaulting Mr Vollmost's friend, Ronald Byrnes, and neighbour Alex Gorman.

The court has heard that one of Mr Vollmost's friends said in the months before disappearance he was worried the gang had placed a $20,000 bounty on his head.

The trial is continuing.

Australian Associated Press