The DNA of someone other than Robert William Pickton was found on key pieces of evidence, the jury in the B.C. pig farmer's murder trial heard Wednesday.

Defence lawyer Marilyn Sandford told the B.C. Supreme Court in New Westminster that DNA from an unknown man was on the buckets in which human remains were found on the Pickton property in Port Coquitlam.

Sandford made the comment as the defence raised questions about the way the search on the property was conducted. The defence contends that although the remains of six women were found on his farm, Pickton did not kill them or participate in their slayings.

Pickton is being tried on six of 26 charges of first-degree murder in the deaths of missing women from Vancouver's Downtown Eastside, with a second trial to be held later. He has pleaded not guilty to all charges.

Defence questions site security

The defence has asked several police witnesses to describe the process of finding two buckets in a freezer in a garage — from the meticulous way in which police officers lifted the freezer lid to how they handled the buckets themselves.

Inside the pails were the decomposing remains of Sereena Abotsway and Andrea Joesbury.

Every officer questioned during the trial has assured the jury that they were extremely cautious to make sure there was no contamination of the evidence.

The jury has heard police had taken DNA samples from Pickton, friends of his who had visited the farm and from police searching the property.

Sandford told the jury they would hear more about the unidentified DNA in the trial.

The defence also questioned the level of security around the farm in the initial days of the search in February 2002.

In the first two days, there were only three officers on the four-hectare property and a fence had not been erected yet.

The officer in charge of security acknowledged the farm was very dark at night and anyone could have walked onto the site from a number of locations without being seen.