A court has rejected the appeal of a farmer convicted of butchering women and feeding them to his pigs in what police say was Canada's worst serial murder case.

Thursday's decision also means Robert Pickton, convicted of six murders, will likely not be tried for another 20 murders with which he is charged. Prosecutors have said that if Pickton's verdict were not overturned, they would not try the other cases because he is already serving the maximum sentence.

Pickton, 59, is serving life in prison with no possibility of parole for 25 years.

However, that is little comfort for some family members of the 20 other women.

"I don't care if he's in jail for 25 years on another case. I care that there's a guilty or not guilty on behalf of my sister and all the other families involved," said Susie Kinshella, a sister of Wendy Crawford, one of the 20.