Defence questions reliability of DNA evidence

The defence in the murder trial of Constable Noel Maitland yesterday raised the possibility that the DNA of missing social media personality Donna-Lee Donaldson could have been transferred through casual contact.

During cross-examination in the Home Circuit Court, defence attorney Chadwick Berry questioned a government forensic analyst about the reliability of DNA evidence found in Maitland’s Chelsea Manor apartment.

The analyst had testified on Tuesday that blood traces discovered on several items – including a brown drape, a black-and-red Puma shoe, and a throw pillow cover – matched Donaldson’s DNA profile.

Donaldson, 24, was reported missing in July 2022 after she was last seen at Maitland’s New Kingston residence. Maitland is currently on trial for murder and preventing the lawful burial of a corpse.

Under cross-examination, Berry challenged the conclusiveness of the DNA evidence, pressing the analyst to acknowledge that genetic material can transfer through ordinary human interaction.

“If a person has sweaty hands and they touch this lectern, is it possible for their DNA to be transferred?” Berry asked.

“It is possible,” the analyst replied, adding that the likelihood depends on “the surface type, the length of contact, and the rate at which an individual sheds skin cells”.

When asked if DNA could transfer through a handshake, the analyst agreed it could, though she added that she could not determine “the rate at which persons shed DNA”.

Berry then pressed further: “And if you are wearing gloves and I shake your hand, would my DNA still transfer?”

“That I cannot speak to directly,” the analyst responded, explaining that “several factors” influence whether transfer occurs.

CHAIN OF CUSTODY

The defence attorney also questioned the chain of custody of a toothbrush used to obtain Donaldson’s reference DNA sample.

“You’re not aware of how that toothbrush was handled by her before it got into the [forensic officer’s] hands?” Berry asked.

“That’s correct,” the witness admitted.

She further admitted that she could not say who would have touched the toothbrush before it was submitted to the laboratory.

Berry later inquired about a DNA swab taken from the trunk of a grey BMW motorcar, to which the analyst replied that the sample contained a mixture from at least four contributors, including one male. However, she confirmed that Donaldson’s reference DNA profile was excluded as a contributor.

Earlier testimony from Donaldson’s mother, Sophia Lugg, indicated she last saw her daughter on July 11, 2022, when Maitland picked her up from their St Andrew home. Lugg said she last heard from her daughter the following morning. Donaldson’s brother testified that he FaceTimed her on July 12 and saw her at Maitland’s apartment, noting the presence of a brown curtain in the background.

The trial continues today before Justice Leighton Pusey and a seven-member jury.

tanesha.mundle@gleanerjm.com