On January 30, the victim withdrew his life savings $30,050 from a Manukau bank while Kumar waited outside.
Hours later he was dead.
Mr Perkins said "potentially very powerful evidence" would come from conversations between Permal and Kumar recorded by police, who bugged the latter's lime green Holden.
Mr Perkins said the jury would be played a recording in which the men discussed the importance of using their phones carefully and how they should act if questioned by police.
"The only way we'll be saved is if our stories match up," it is alleged they said.
When police interviewed Permal, two weeks after Mr Prasad was found dead, he denied knowing or ever having met the victim and said he had gone straight home from work on the night in question.
However, when police played him the recording from inside the car he changed his story.
"I want to tell the truth, I'm being honest this time," Mr Perkins said he told officers.
He quickly pinned the murder on Kumar and said he only helped him purchase the petrol -- which was allegedly used to burn the victim to death -- because he thought Kumar's car had run out of fuel.
Permal told interviewing officers that they had stopped in Karaka and he stayed in the car while his associate set the fire.
In their respective statements, both accused told police they had gone to the Pelican Club -- a brothel in Newton -- late that night.
Permal said he was paid just over $4000 for his role.
In his interview Kumar admitted to police he had seen the victim in Papatoetoe on the afternoon of his death but completely denied any role in his murder.
Mr Perkins suggested he was being "rather careless with the truth".
Earlier today the jury heard how Permal had attempted to arrange an urgent flight to South Africa the day after the alleged incident.
A travel agent will give evidence that he explained his partner was in intensive care there and he needed to leave the country as soon as possible.
Alarm bells initially rang with Mr Prasad's family when his father checked his son's bank account and found $30,050 missing on January 30.
The 21-year-old man's smouldering body was found early the next day by a woman walking her dog on McRobbie Rd in Kingseat.
Police were able to identify the victim only after analysing the fingerprints and pathologists were almost certain the man had been alive when doused in petrol and set alight.
Mr Perkins said medical professionals would give evidence of finding the accelerant in Mr Prasad's bloodstream and lungs which led them to that conclusion.
The trial before Justice Geoffrey Venning and a jury of six women and six men is expected to last four weeks.