WINNIPEG – Prosecutors have begun laying out their DNA evidence at the trial of alleged Candace Derksen killer Mark Edward Grant.
Grant has pleaded not guilty to a charge of second degree murder in the infamous 1984 death of Derksen, a 13 year old girl who vanished while walking home from school.
Grant was arrested decades after Derksen’s body was found frozen and tied up in a shed, in the winter of 1985.
Mitochondrial DNA testing done by a Thunder Bay lab called Molecular World was used to link Grant to the crime.
A former scientist with the lab, Arlene Lahti testified at the trial on Wednesday. She walked court through painstaking specifics about how the testing worked, often being asked to stop by the judge who was taking notes.
Lahti did not test any samples from Grant himself, but did test some from several of his maternal relatives. She told court she didn’t know who any of the people were. It was other scientists from the lab who would eventually test hairs and DNA extracts from twine used to tie Derksen that pointed police to Grant.
Under stiff cross examination from Grant’s lawyer, Saul Simmonds, Lahti admitted she had no special training in forensics and that mitochondrial DNA testing “could be” susceptible to contamination. Later, she admitted it could be less “discerning” than nuclear DNA testing, a different form of the testing.
Simmonds repeatedly made reference to how Lahti was not technically an “expert witness” in the legal sense and appeared to question the degree of her knowledge in certain areas.
He had questions about the protocols followed by her lab and the type of proficiency testing that was done to ensure work was being completed properly.
This was the first of several straight days of painstaking and scientific evidence related to the DNA.
Defence lawyers have already told court they will argue testimony from the next witness, Curtis Hildebrandt, another scientist at the lab, should not be admissible. They will argue he’s not a qualified expert and point to other issues that should disqualify his evidence. It is evidence that plays a crucial role in linking Grant to the murder and is key to the prosecution’s case.
Grant was convicted of killing Derksen in 2011, largely because of the DNA evidence presented to the jury, but that conviction was overturned after an appeal.
This new trial is being heard by a judge alone and is expected to last several more weeks.