The judge in the murder trial of Robert William Pickton told jury members they can find the accused guilty even if they conclude that other people took part in the deaths of six Vancouver women.

Robert William Pickton is on trial for the deaths of six women who went missing from Vancouver's Downtown Eastside.
(CBC)

Justice James Williams began his instructions to the 12-member jury Tuesday morning at the B.C. Supreme Court in New Westminster by reviewing evidence and going over the legal principles that apply to the case.

Pickton, a Port Coquitlam pig farmer, is charged with first-degree murder in the deaths of Sereena Abotsway, Mona Wilson, Andrea Joesbury, Brenda Wolfe, Marnie Frey and Georgina Papin. He'll face another 20 murder charges at a later date.

He has pleaded not guilty to all charges.

Williams started his long address — expected to take three full days to complete — by thanking the jury, which consists of seven men and five women, for its long hours of work.

The judge told jury members they must not let 20 other murder charges against Pickton affect their deliberations in this case.

He said it's not necessary for the jury to find that Pickton acted alone, and they may find he acted with others even if they don't know who.

During its closing arguments, the defence said DNA evidence pointed to other people who were often visitors to Pickton's farm.

Williams also said the jurors must be certain beyond a reasonable doubt that Pickton killed the women, because it's not enough that they think he may have or probably killed them.

He also touched on witness credibility, in particular how the jurors should regard the evidence of witnesses who've been in trouble with the law.
 
Numerous witnesses, including three of the prosecution's key witnesses against Pickton — Scott Chubb, Lynn Ellingsen and Andrew Bellwood — have criminal records for offences that include fraud and drug trafficking.

Williams told jurors a criminal record should be considered when assessing the credibility of a witness but it shouldn't automatically destroy or impair credibility.

The judge will continue with his instructions to the jury Wednesday.

With files from the Canadian Press