It's been three years since a stage collapsed in Downsview Park, killing Scott Johnson and injuring three others before a Radiohead concert.

Three years that Johnson's father, Ken, has waited for answers and for someone to take responsibility.

An engineer working at the concert, concert promoter Live Nation Canada, Live Nation Ontario and Optex Staging and Services are all facing charges in a trial before the provincial Ministry of Labour this week.

All four have pleaded not guilty.

"Scott was our only boy so this was quite devastating, really," his father said. "He was a happy guy."

Johnson spoke to his son regularly, even though he spent so much of his career on the road. He worked as a drum technician, tuning instruments for the Killers and Keane before being called up to work with Radiohead.

Scott Johnson

Scott Johnson, 33, travelled the world as a drum technician. (Contributed)

The concert was the last one on Radiohead's summer tour in 2012.

"To come and work with Radiohead was a pretty quick rise to the top of the tree. If you're Radiohead's drum tech then people in the business are going to know who you are."

Hours before the band was going to take the stage, it collapsed.

Another of Radiohead's crew members testified at Tuesday's trial.

'No one's manning up'

And the band's manager, Adrian Bullocks, said he was disappointed no one had taken responsibility.

"No one's manning up and saying, 'Look, it's our responsibility and we share responsibility,' and it's really quite… disrespectful in a way."

Johnson plans to stay for the trial and said he'd also like to plant a maple tree for his son at Downsview Park.

"It's also one of the best trees for making drums," he said.

Corrections

  • An earlier version of this story incorrectly reported the name of one of the companies facing charges as Optics Staging and Services. In fact, it's Optex Staging and Services.
    Nov 18, 2015 11:37 AM ET