Six people have now been charged in connection with the homicide investigation - five teenagers and a 33-year-old woman.
Whorrall, a PhD student at Auckland University, was killed in an attack at a Meadowbank bus stop on April 19 this year.
The Operation Aberfeldy team has since been investigating the homicide.
Today, three people were charged after police searched properties in Kaikohe and the Auckland suburbs of Mt Wellington and Manurewa.
Detective Inspector Glenn Baldwin said as a result, two 18-year-olds and a 17-year-old have been charged jointly with murder and aggravated robbery.
"We have spoken with Kyle's mother this morning to keep her updated on this development, and it is not lost on us the profound impact this event has had on her family," Baldwin said.
The investigation would now shift towards moving into the prosecution phase, he said.
"At this point we believe we have identified those allegedly involved, however the investigation remains ongoing."
An 18-year-old man would appear in the Kaikohe Youth Court and the other two in the Auckland Youth Court today.
