Ambrose Clarke bought a piece of black plastic from a work acquaintance "for a small job" the day before his former business associate was allegedly killed and wrapped in plastic.
Trevor Reid told a Supreme Court jury today that Mr Clarke came to his house in Bateman on the evening of May 29, 2011 and bought a piece of plastic after telling him he had a job on the following day.
Mr Clarke and his brother Xavier deny murdering High Wycombe businessman Peter Davis whose body was found wrapped in plastic in the boot of his car on May 31, 2011.
Mr Reid said Mr Clarke told him he "had a small job on" and also asked if he had any protective clothing, which he thought was "a bit strange".
He testified that Mr Clarke had asked if he had any coveralls.
He said he had a large piece of plastic which he had used for a bakery job "maybe a month or two before" and Mr Clarke cut a piece from it which he then placed in the back of his ute.
The jury heard police attended Mr Reid's house and seized a piece of black plastic.
Forensic examination officer Senior Constable Derek Pitcher testified today that the piece from Mr Reid's house and the piece of plastic that Mr Davis' body was wrapped in "were at some stage the same piece of plastic".
He said he examined both pieces - one of which had stains which were consistent with blood - and there were a lot of "creases and folds that continued from one piece of plastic into the next piece".
Mr Reid said Mr Clarke had told him that there had been a "falling out" with Mr Davis and that he and another business associate believed they were owed money by Mr Davis.
He said it "appeared on the conversations that they'd left on good terms" but he said Mr Clarke appeared upset when he mentioned Mr Davis.
Under cross examination, Mr Reid admitted the piece of plastic had been used before, was dusty, had been handled and left in his backyard.
The trial also heard yesterday a close friend of Mr Davis, Joanne Green, received an email from Mr Davis' account at about 9.30am on May 30, 2011 which said "coming over now" and "I'm really horny".
Ms Green said it was "definitely not" the sort of email she would ordinarily have received from Mr Davis.
She said when she finished work that day, she had a voicemail from Mr Davis' wife Jennifer in which she sounded "desperate" and that Mr Davis was missing and asking for her to call.
Ms Green said she called Mrs Davis, who asked if she had heard from her husband, and she then tried unsuccessfully reaching him on the two mobile numbers she had for him.
Prosecutors allege the email was sent to lead people to believe Mr Davis had "run off with some one" and "put them off the scent that he lay dying" in the boot of his car.
Ms Green told the jury she became close friends with the Davis family after moving in across the street and they had remained close friends after she and her family moved to Karratha about eight years ago.
She said to spoke to Mr Davis on May 25 after inviting him to lunch as she was in Perth before returning home to Karratha after a trip to Melbourne, but he was unable to attend as he was "up north working".
The jury has also heard there was an email from Mr Davis' account on May 27 to Ms Green which said "I love your goodnight note".Ms Green said she did not see either email and rarely used the email account it had been sent to.