Dylan Cossey, pictured arriving at court on February 12, was found guilty of four charges of manslaughter relating to the deaths of four people in an alleged street-racing incident south of Hamilton in June 2016.

A High Court jury has found a driver guilty of manslaughter in the case of an alleged street race south of Hamilton that ended in a head-on smash that killed four people.

Dylan Cossey, 20, fled from the crash site near Hamilton Airport on the night of June 24, 2016, with his co-defendant Stephen John Jones, 20, in the front passenger seat.

The pair have been standing trial in the High Court in Hamilton, where they faced four counts each of manslaughter relating to the deaths of Hannah Leis Strickett-Craze, 24, Lance Tyrone Robinson, 28, and Paul de Silva, 20, all from Waipa, and Jason McCormick Ross, 19, from Taranaki. The four died after the Nissan Skyline they were travelling in lost control and crashed.

CHRISTEL YARDLEY/STUFF Stephen John Jones, pictured arriving at the High Court in Hamilton on February 12, gave evidence on Thursday.

Cossey was found guilty of the manslaughter charges, while Jones was found not guilty on all four manslaughter charges.

The public gallery was packed with friends and supporters of both the victims and the defendants, when the jury returned with their verdicts at 11.40am.

There were shrieks of support from some of the supporters of the victims as the verdicts were read out by the trial foreman. Cossey and Jones largely remained impassive.

FACEBOOK Jason McCormick Ross, 19, was one of four people killed in the high-speed crash near Hamilton Airport.

Both men will be sentenced on April 20. Cossey was granted bail and is subject to a 24-hour curfew. He is also banned from driving.

Jones also received bail and is subject to a 7pm to 7am curfew.

The jury had retired to consider their verdicts at 1.35pm on Monday, following the summing up of Justice Anne Hinton.

SUPPLIED Lance Tyrone Robinson, 28, died when the Nissan Skyline he was driving crossed the centre line and hit an oncoming van.

The alleged race between the Honda Integra Cossey was driving and the Skyline reached estimated speeds of more than 150kmh. It came to a sudden end when the Nissan lost control and collided with an oncoming van about 10pm.

Both Cossey and Jones were also charged with causing injury to the van's driver and failing to stop to ascertain injury. The van driver suffered multiple leg fractures and had to be cut from his vehicle. Cossey was found guilty of this also, while Jones was not guilty. Both were guilty of the failing to stop charges.

Jones was also found guilty of one count of attempting to pervert the course of justice - a charge that relates to his alleged editing of the video he took of the crash and the moments leading up to and after it, removing 20 seconds of evidence before handing his phone in to police.

SUPPLIED Paul De Silva, 20, died at the scene of the crash on State Highway 3.

The Crown case, being handled by Duncan McWilliam, contended that Cossey, egged on by Jones, was racing against the occupants of the Skyline - an illegal act - and as such he was culpable of manslaughter.

Cossey's lawyer Philip Morgan QC has argued his client cannot possibly be guilty of any of the charges he was facing as he was not racing and that it was Robinson, who was driving the Skyline, who was solely responsible.

Jones's counsel Russell Boot said his client was merely a passenger who did nothing more than film the incident on his iPhone.

SUPPLIED Hannah Lei Strickett-Craze, 24, died in the crash on June 24, 2016.

Additionally, Jones had trimmed the length of his footage with no intention of hiding any footage of Cossey, the other car or the speed the Integra was doing just before the crash, Boot said.

The case had not been a particularly long or complex one, Justice Hinton said. The jurors should keep in mind they were judging two separate individuals.

"Because they are jointly charged does not mean they must both be guilty or both not guilty."

Whether they believed Cossey or Jones lied, either in Cossey's interview with the police - played in court as part of the Crown evidence - or during Jones's first-hand giving of evidence in court in his own defence, was something they could take into consideration as part of their overall deliberations.

The judge gave the jurors a "question trail" which provided them with a structure to base their deliberations around. One such question trail regarding the first charge against Cossey, which alleges he caused the death of Robinson through an illegal act and thereby committed manslaughter.

The jurors were asked:

Are you sure that Dylan Cossey was operating a motor vehicle on a road?

Are you sure that he was operating the motor vehicle in a race?

Are you sure that he intended to operate the motor vehicle in a race?

Are you sure that the race was not authorised by law?

Are you sure that Dylan Cossey caused the death of Lance Robinson by operating a motor vehicle in a race?

The jurors had to consider each of the other charges the pair are facing with the assistance of similar question trails.

Justice Hinton told the jury before they went out that they must come to their verdicts solely on the basis of the evidence before the court. This meant that any knowledge they had of the case before the trial began, any media reports on the trial, and anything anyone might have said to them about the trial while it was under way should be put firmly out of mind.