RCMP test tube leaked DNA linked to B.C. 13-year-old's death, murder trial hears
RCMP DNA analyst says defective test tube was 1 of more than 20 and the remainder were secure
WARNING: This story contains graphic content and may affect those who have experienced sexual violence or know someone affected by it.
An RCMP lab worker analyzing DNA samples recovered from the body of a 13-year-old Burnaby girl said a defective test tube caused a sample to leak during a transfer — but contends it was the only incident within the batch of tubes they handled.
Maria Li, a forensic DNA analyst with the RCMP Forensics Laboratory, testified at the Ibrahim Ali trial and recalled her work extracting DNA from samples related to the investigation of the death of a Burnaby teen whose body was found in the city's Central Park in 2017. The samples were of both skin and sperm cells.
Li said robots were used to extract the DNA from the cells in July 2021 and then create subsequent DNA profiles. She testified that once the profiles were created, lab workers returned the DNA to test tubes so they could then be given back to police investigators. Li said there were 20 tubes to begin with. The DNA extraction process doubled the number of tubes needed, bringing the total to 40.
During this transfer, Li said they noticed skin DNA was leaking through the bottom of a test tube, which had a small pinhole at the bottom. The remainder of the sample was transferred to another tube.
Li said the tube had a manufacturing defect and told prosecutors the incident was the only issue recorded by lab workers during the analysis, which followed all standard operating procedures, including operational reviews and sign-offs by other qualified DNA analysts. The remaining tubes were secure, she said.
"My controls were satisfactory," Li told prosecutor Colleen Smith. "No contamination was detected."
Li is among the DNA witnesses called to testify during the first-degree murder trial of Ibrahim Ali.
WATCH | Police search of Ibrahim Ali moments after his 2018 arrest played for jurors:
In her opening statement, Crown prosecutor Isobel Keeley said a 13-year-old victim, whose name is protected by a publication ban, was passing through Burnaby Central Park on July 18, 2017, when she was attacked and dragged into the woods before she was sexually assaulted and strangled to death.
Prosecutors say DNA evidence will connect Ali to the crime.
Timeline, contamination questions
During cross-examination, defence counsel Kevin McCullough asked Li if she knew why she was performing analysis on samples that were four years old. Her work was done in 2021, but the alleged murder took place in 2017, and Ali was arrested in 2018.
Li said she did not know nor was ever told the particulars of the case or who the samples came from.
Thus far in the trial, no witnesses have testified as to why these samples were analyzed for DNA after Ali was in custody. Li did note the pandemic created a backlog for lab work but was unsure if it had an impact on this analysis.
McCullough also asked about the defective tube, asking if the sample could have been contaminated. Li said the hole was only discovered post-analysis, and no contamination was found.
Li said other test tubes at the lab come from the same manufacturer, but no similar defects were recorded during her work.
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