B.C. Attorney General Wally Oppal says the Crown will appeal Robert Pickton's second-degree murder convictions, partly because he has always believed Pickton planned to kill his victims.

But the attorney general said there is also a second reason for the appeal based on a technical legal concern. If the defence appeals and a retrial is allowed, that trial would be based on second-degree murder — not the original first-degree murder charges.

With the 30-day appeal deadline only two days away, Oppal told the Canadian Press the Crown expects the defence will also file a notice of appeal of the former pig farmer's conviction.

Linda Mueller, a spokeswoman from the attorney general's office, told CBC News on Sunday the appeal papers will be filed Monday.

Pickton was convicted Dec. 9 on six counts of second-degree murder in connection with the deaths of women from Vancouver's Downtown Eastside, and sentenced to life in prison with no chance of parole for at least 25 years.

The 58-year-old from Port Coquitlam, B.C., still faces murder charges in connection with the deaths of 20 other women, but no decision has been made on whether to hold a second trial, Oppal said last month.

Oppal couldn't say how the appeal of the first trial would affect a possible second trial on the 20 other murder charges against Pickton.

However, he said it would be prudent to see what course the appeal takes before that trial proceeds.