Sainey Marong has been found guilty of murdering Christchurch sex worker Renee Duckmanton.
The 22-year-old's badly burnt body was found on Main Rakaia Road in May 2016.
Ten days later Marong, the 33-year-old Gambian-born butcher, was arrested and charged with her murder.
Ms Duckmanton was last seen in Christchurch's red light district, near Manchester and Peterborough Streets.
During the trial the court heard from Crown Prosecutor Sean Mallett that Marong strangled Ms Duckmanton after employing her for sex on 14 May.
He described how Ms Duckmanton's body was found the next day.
"[Renee] left for work ... the next day members of the public noticed a fire on the grass verge along Main Rakaia Road ... as good samaritans, they stopped to attend the blaze and call the fire service," he said.
"What they had in fact stumbled on was a grisly sight ... the half-naked and burning body of Renee Duckmanton."
The court heard that a police investigation found Marong purchased about two litres of petrol from a local service station which he allegedly used to set the victim's body on fire after dumping her body.
A beanie and a lighter, both containing Marong's DNA, was found at the scene, as well as a sheep's tongue.
Mr Mallett said several unusual internet searches were also found on the defendant's phone.
"In the weeks leading up to the murder, the defendant searched on his phone 'What kidnappers use to make someone unconscious' as well as searches for chloroform and chemical suppliers in New Zealand," he said.
"He accessed a web article 'How to kidnap girl, an informative guide' and typed into Google 'How to track a phone'."
Other topics, including necrophilia, were also found amongst the defendant's web history.
Marong gave evidence in his defence during the trial.
He told the court while he does not deny killing Ms Duckmanton, he denies responsibility for the murder charge - claiming he was mentally imbalanced.
During his defence he spoke about having diabetes which he believes led to toxins entering his brain, and his declining mental health.
He said this caused him to become fixated with sex workers in Christchurch's red light district on Manchester Street, where he would drive to up to 10 times a day.
Asked why he spent so much time visiting websites involving necrophilia, he said this was a sign of his psychosis and how disconnected from reality he was.
However, asked if he wanted to kill somebody, he agreed that he did.
During cross examination, crown lawyer Pip Currie said his actions were premeditated and that he was in control.
She said this continued after the killing when he cleaned his car to remove DNA evidence and carried out internet searches on whether setting a body on fire removed DNA evidence.