Edgeworth pointed out inconsistencies in Coughlan’s story, including claims he had injured his hands climbing a tree after the incident, which she called “slightly odd”.
She added the defendant’s blood had been found on Collins’ recovered bike because he had likely injured himself in the “ferocious and horrendous” attack.
“The retrieval of the clothing from the pond, again, all forensically linked Zach to that crime. So it was a really interesting and complex forensic picture,” she said.
In a statement issued outside court, surrounded by Coughlan’s family, Edgeworth described the murder as “meticulously planned”.
“The brutal nature of what he did cannot be underestimated,” she said.
“Rather than calling for medical help he did everything to protect himself.
“He feigned shock and the lies continued, both to police and friends in the hours and days after what happened.”