A gunshot residue expert told the Supreme Court that she could not say how or when a particle of gunshot residue came to be on a shoe seized as part of an investigation into a double murder.

Tarah Helsel, an expert from Pennsylvania-based RJ Lee Group, said that while the particle could mean the shoe was near a firearm when it was discharged, it could also have been transferred on to the shoe from something else.

“There’s no way for me to say when or how they got there,” she said.

Ms Helsel told the court earlier this week that she tested several swabs taken from the hands and upper body of Syhon Akinstall two days after a deadly 2021 shooting at the Robin Hood Pub and Restaurant.

She explained that she was specifically looking for particles that contained lead, barium and antimony — three metals found in the primer of ammunition.

Ms Helsel said that swabs taken from Mr Akinstall’s hands and his left ear revealed several “two-component particles”, while a grey-and-white sneaker mailed to her was found to contain three two-component particles along with a single three-component particle.

Under cross-examination yesterday, Ms Helsel agreed that a single particle of gunshot residue was a low amount.

She also told the court that such particles do not degrade and can remain on an item indefinitely, adding that they have been found on items that had been in storage for more than a decade.

However, she explained that the particles can be transferred between sources through physical contact or washed off.

Ms Helsel added that she could not link the gunshot residue to a specific weapon or type of ammunition as the same elements are found in the primer of most cartridges.

She also said that police officers could inadvertently transfer gunshot residue particles on to a suspect they are dealing with.

Ms Helsel confirmed that while she had carried out a study of environmental gunshot residue in Bermuda, she did not test the interiors of Hamilton Police Station, the Police Recreation Club or armed-response vehicles.

However, she said that five officers took part in an anonymous local study looking for gunshot residue particles on people’s hands.

That study revealed no such particles on the hands of 100 volunteers. However, two people were found to have two-component particles on their hands.

In re-examination, Ms Helsel was asked what effect riding on a motorcycle would have on any gunshot residue deposited on a rider’s clothing.

“I would expect that would cause particles to be removed because of the airflow while riding,” she said.

Mr Akinstall, 22, has denied the murders of Ayinde Eve and Micah Davis, as well as the attempted murders of Troy Eve Burgess and Derrick Golding, a police sergeant.

He also denies four counts of the use of a firearm to commit an indictable offence, namely the alleged murders and alleged attempted murders.

He has been charged in connection with a shooting at the Robin Hood Pub and Restaurant in Pembroke on October 26, 2021.

The trial continues.

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