The sister of Thomas Svekla blamed anesthetics for discrepancies between her testimony and her previous statements given to police, as defence lawyers questioned her Tuesday in an Edmonton courtroom.

Under cross-examination, Donna Parkinson said she had just undergone knee surgery the day before and was in significant pain when she gave her statements to police in June 2004.

Defence lawyer Robert Shaigec questioned Parkinson about her testimony on Monday where she told the court she saw her brother with very bad scratches on his arms just a few days before the body of Rachel Quinney was discovered.

Shaigec said Parkinson had told police in a previous statement that the marks were "faint" and "very light".

Parkinson also told investigators Svekla had commented on finding a skeleton just before police were notified of Quinney's body in a wooded area near Sherwood Park.

Thomas Svekla, 39, is charged with two counts of second-degree murder and two counts of offering an indignity to a body in the deaths of prostitutes Theresa Innes, 36, and Rachel Quinney, 19.

The trial run for four months.