Thomas Svekla's defence lawyer, Robert Shaigec, leaves court in Edmonton on Tuesday. ((CBC))

Thomas Svekla's lawyer spent the day Tuesday trying to poke holes in the testimony of a key prosecution witness in the double murder trial — Svekla's sister.

Robert Shaigec questioned Donna Parkinson about inconsistencies between her statement to police in June 2004, after Rachel Quinney's body was found east of Edmonton, and testimony Parkinson gave at the trial Monday.

Svekla is charged with second-degree murder in the death of the 19-year-old prostitute, whose body he says he stumbled across while smoking crack cocaine with another prostitute.

Parkinson testified her brother had come to her a week before Quinney's body was found, sobbing, "I did something really bad. I did a bad thing. You're going to hate me."

She also described him as being covered in scratches.

Shaigec asked Parkinson why she didn't mention that when she was questioned by police after Quinney's body was found.

Parkinson repeatedly insisted her court testimony was accurate and blames leg surgery she had before making her police statement and the after-effects of anesthetic for the discrepancies.

"Do you know what I think of this statement? I don't think it should be used," Parkinson said, waving a copy of the police statement.

The defence did not take issue with Parkinson's testimony that in May 2006, she and her husband opened a hockey bag belonging to her brother and found a body tightly wrapped in plastic.

The body turned out to be that of Theresa Innes, 36, the second prostitute Svekla is accused of killing.

The trial in Alberta's Court of Queen's Bench is being heard by judge alone. It is expected to last about three months.