Expert: Tucker’s gait similar to suspect
An expert told the Supreme Court that Kiari Tucker had a similar stride to a suspect caught on tape before the murder of Morlan Steede.
Barry Francis, a British forensic gait analyst, said he spotted several similarities in CCTV footage between the way Mr Tucker walked and the way the suspect walked.
But Dr Francis accepted that forensic gait pathology was still in its infancy and that only one scientific study had been done on the methodology he used.
Mr Tucker, 22, denies murdering Mr Steede in the Deepdale area of Pembroke on November 3, 2017.
The court heard earlier that police tracked Mr Tucker's movements on the night of the shooting through police and private CCTV cameras.
Dr Francis told the court on Thursday that he had been sent footage of the suspect in the Deepdale area along with surveillance footage of Mr Tucker from the same evening.
He explained that as a podiatric surgeon, he had spent years in observation of the gait — the style of walking — of patients.
Dr Francis said that forensic gait analysis was the process of making observations in video footage to compare and identify individuals.
He said: “I look at unknown footage and identify any features and flow.
“When that is completed I review known footage, custody or surveillance footage, look at the features or flow found there and see whether there is any comparison between the two sets of findings.”
Dr Francis added: “Forensic gait analysis at this time can only be classified as class identification. It doesn't make a unique identification as DNA or fingerprints would.”
He said he made several observations about the suspect seen in the Deepdale area, identified in court as Man X.
Dr Francis added: “As he walked, I observed a lowering of the left shoulder as the left foot came forward. I also observed a turning out of the left foot and noted that the feet were close together.
“As the subject turns to the left, I observed a long stride or step length.”
He also said that when the suspect's left foot moved forward, he noticed an inward swing — or “slight collapse” — of the left knee.
Dr Francis said he noticed the same traits in surveillance footage of a man identified as Mr Tucker, recorded the same evening.
He said: “In with the left knee, lowering the shoulder as the left leg goes forward, and the pattern continues.
“You can see the close gait, feet close together, the turning out of the left foot.”
Dr Francis told the court under cross-examination by defence counsel Susan Mulligan that the majority of his career had been spent in clinical work and he had been involved in forensic work since 2004.
He said there had only been one published study on error rates associated with his analytical techniques and it had found a 27 per cent error rate.
However, Dr Francis added: “A closer review of that study will show that the people involved were students, not current practitioners.”
He also accepted that cognitive bias was an issue as analysts usually receive only the “question” footage and recordings of identified police suspects.
Dr Francis said: “There's no way to guard against the fact that the police are saying there's some connection between the two.
“That's why in my particular practice I get a verifier and ask them to review the footage independently.”
The trial continues.
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