CALGARY - The loss of a major expert witness on behalf of the state of Montana could help Canadian Ronald Smith's attempt to avoid death by lethal injection.

Smith, who is from Alberta, was convicted in 1983 of shooting two men in the state while he was high on drugs.

He asked for and was given a death sentence but later had a change of heart and has had a number of execution dates set and overturned.

A hearing is scheduled for next July on whether new lethal injection drugs being proposed by the state comply with execution rules.

A judge ruled in 2012 that lethal injections were unconstitutional and there was a lack of training for people who administer the drugs.

But the expert Montana was going to use in its argument has withdrawn his services, and the state has been unable to find a replacement.

Ron Waterman, an American Civil Liberties Union lawyer, says it may be possible to get the court to consider issuing a ruling based on the evidence it already has.