A man has been sentenced to seven years jail for manslaughter after he pursued a 15-year-old boy, who he mistakenly thought was riding his stolen motorcycle in Perth's southern suburbs, into a passing SUV.

Key points: Mitchell Chase, 15, died after his motorbike collided with an SUV in December 2016

Mitchell Chase, 15, died after his motorbike collided with an SUV in December 2016 He was being chased by Jude Nathan Francis, who mistakenly thought the bike was his

He was being chased by Jude Nathan Francis, who mistakenly thought the bike was his A judge has sentenced Francis to seven years in prison, saying he alone was responsible for the teen's death

Mitchell Chase died in hospital after his trail bike collided with the vehicle at an intersection in the residential suburb of Aubin Grove on December 28, 2016.

The 15-year-old was being pursued by Jude Nathan Francis, who pleaded guilty to manslaughter, failing to stop and provide assistance and failing to report the incident.

Francis, 26, was chasing the teenager because he thought he had stolen his motorcycle, and was also driving while his licence was suspended.

Mitchell Chase was killed when his trail bike collided with a car at an intersection. ( Facebook: Mitchell Chase )

During sentencing, Justice Bruno Fiannaca said while he accepted Francis now felt remorse for the teenager's death, his actions at the time were "callous and shameful".

"You made the choice to act as a vigilante and place him in danger," he said.

"You alone are responsible for his death."

Francis checked bike before fleeing crash scene

Justice Fiannaca said he did not believe what Francis had told police when he said he fled the scene and did not report it because he was panicked and in shock.

The crash happened on Giverny Gardens in the southern Perth suburb of Aubin Grove. ( ABC News )

He said that did not match with someone who had taken the time to check to see if the motorcycle was his by looking for distinctive stickers.

In front of a packed courtroom, Justice Fiannaca said it was clear Francis — who has a four-year-old daughter — came from a supportive family who had witnessed the grief it had caused him.

A psychological report found Francis was suffering from some form of acute post traumatic stress as well as both anxiety and depression.

Justice Fiannaca said while all of this was taken into consideration, the impact of Francis' actions on Mitchell's family had been extreme.

Mitchell's parents Denise and Wayne Chase both broke down in tears when Justice Fiannaca spoke about their victim impact statements, which he labelled "heart-wrenching reading".

'We struggle every day with the loss'

Speaking outside court flanked by a large group of Mitchell's friends, Ms and Mr Chase said while they were happy with the sentence, they had been devastated by the loss of their son.

"We just hope that this is a lesson for anybody in the future that thinks of doing anything similar," Ms Chase said.

Mitchell's mother Denise Chase said her son was too young to be taken from his family. ( Facebook: Mitchell Chase )

"He had such a bright future ahead … how much we struggle every day with the loss of Mitch. Just walking into an empty room, or just smelling his clothes to try and feel him, or talk to an empty space.

"Mitch was a strong person and he stood up for so many people.

"To know that he was so scared, that's part of my nightmares at night."

Mr Chase said his son was his hero.

"He was the most unique character I ever met," he said.

"He was just confident. He was my hero. He was everything I wished I could be.

"His success, his drive, his love of life — I don't go more than two minutes without thinking about him."

Mitchell's father wants to put Francis 'out of his mind'

Mitchell Chase's mother Denise hugs a supporter outside a Perth court. ( ABC News: Briana Shepherd )

Ms Chase said they felt a lengthy prison term, taking Francis away from his own parents, would go some way to helping them understand what losing a child was like.

"His mum and dad will know what we feel like. We've not seen Mitch for 17 months and it feels like a lifetime," she said.

Mr Chase said he now wanted to put the man responsible for his son's death out of his mind.

"From now on I don't want to give him any thought," he said.

"Hopefully I never come face to face with him [or] see him, [and] give as little time as possible thinking about him."

Mitchell's parents spent some time embracing their son's friends before leaving the courthouse.

Mitchell Chase's father Wayne Chase says he hopes to never come face to face with Francis again. ( ABC News: Briana Shepherd )

Worse than the Elijah Doughty case, judge says

Justice Fiannaca compared the case to the death of Elijah Doughty in Kalgoorlie-Boulder in August 2016, after which a man was found not guilty of manslaughter and jailed for three years on a lesser charge.

Supporters of Elijah Doughty were angered by the sentence handed down last July over his death. ( ABC News: James Carmody )

He said in that case, Chief Justice Wayne Martin had sentenced a man who had, like Francis, engaged in a reckless act of chasing a young man on a motorcycle believed to have been stolen.

But Justice Fiannaca said while the cases had some similarities, there were also differences — such as how the man chasing Elijah had stopped after the accident, and how the chase had occurred on a track, not a suburban street.

He said in his view, the circumstances of Francis' offending were worse.

In addition to the prison sentence, Francis was banned from holding a drivers licence for three years, with the disqualification to be served once he is released from prison.

He will be eligible for parole in five years.