Police have released new details about the ongoing homicide investigation into the bus stop killing of American student Kyle Whorrall.

Detective Inspector Glenn Baldwin revealed today at Auckland City Police Hub that police discovered a machete in Maybury Reserve in Glen Innes yesterday. He would not confirm if it was the murder weapon.

Whorrall, 33, was killed in an attack in St Johns during Easter Weekend while he was waiting at a bus stop.

Two people were arrested by the Operation Aberfeldy investigation team in late April; however, police have maintained that others were in the car on the night Whorrall was fatally attacked.

University of Auckland student Kyle Whorrall was attacked at a St Johns bus stop at Easter and died later in hospital. 

Detective Inspector Glenn Baldwin said a 16-year-old male remains before the High Court at Auckland, charged with Whorrall’s murder.

A 33-year-old woman is before the Auckland District Court on two charges of being an accessory after the fact to murder.

Baldwin emphasised today that the investigation into Whorrall’s alleged murder “is not over” and made a fresh appeal to the public for help.

“There are people in the community who have intimate knowledge of this crime,” he said

“There have been recent developments in the case. Police are determined to hold the killers to account. The police need assistance from members of the community. Now is the time to come forward… This is the opportunity to do the right thing."

Baldwin would not say today what led a specialist search team and a police dog team to Maybury Reserve, but “it wasn’t by mistake”.

He said police were not certain if the machete was the murder weapon, but police were keeping an open mind.

It was a rusty machete which “had been in the weather for some time”.

Baldwin said “most of the people involved” in the incident were in Auckland.

He said he spoke with Whorrall’s mother this morning.

“It’s an incredibly tough thing for her to deal with… We just want to find out what happened to Kyle.

“He did nothing wrong.”

Baldwin said Kyle was confronted by two assailants at the bus stop.

The black SUV had been circling around the spot where Whorrall was sitting, security camera footage showed.

Baldwin launched a renewed appeal for information last month, pleading with those involved with the student’s death to “do the right thing”.

“We know there were others in the vehicle that night, and I’m asking people with that information to come forward now.”

A floral tribute at the bus stop on St John’s Rd, where US student Kyle Whorrall was killed. Photo / Alex Burton 

Whorrall’s mother, Carole, told the Herald she wanted her son to be remembered for his life, not his death, when she spoke after his memorial in May.

“Kyle was a brilliant, gentle and deeply caring person whose love for the natural world shaped his life and inspired those around him,” she said.

“He was dedicated to making a difference and about to embark on a brilliant career. He was deeply loved and admired by his family.”

The Ōrākei Local Board arranged for a memorial service at St Johns Bush, where a pōhutukawa was planted, with Carole in attendance.

Whorrall, who was originally from Los Angeles, was in the last stages of a PhD in entomology at the University of Auckland and was based at Landcare Research in St Johns.

Police claim two occupants of the erratically driven vehicle attacked Whorrall while he was sitting alone at a bus stop in Meadowbank on April 22.

Whorrall was struck with a “long” weapon, suffering multiple head injuries, and later died in hospital.