"We submit he's remorseless, he's controlling, he's possessive and he's vicious and he murdered her," he said.
Turner manipulated his parents and told his mother to change her story, the court was told.
"It is clear Elliot pulled the strings."
In summing up the defence case, Anthony Donne QC said Turner was "brash, flash, boastful, volatile, obsessive, possessive and obsessed" but that did not prove he was a murderer, and he acted in self defence.
There was plenty of evidence before the court that Emily was capable of striking back, he said.
Turner was arrested following Emily's death on May 7 last year but was then released on bail.
Emily was born in Britain but her family moved to New Zealand when she was nine and she was raised in Auckland, where she attended Hauraki School, Westlake Girls High and Takapuna Grammar.
She had returned to study in Britain and lived with her grandparents in Bournemouth while continuing her studies there.
-APNZ