Toronto Police and emergency personnel are working to determine the cause of the stage collapse that killed Radiohead’s drum technician and injured three other crew members at Downsview Park Saturday afternoon, just an hour before gates were scheduled to open for the British band’s concert.

The band said it was devastated over the death of Scott Johnson, a U.K. citizen in his 30s who was trapped under the rubble and pronounced dead at the scene.

“We have all been shattered by the loss of Scott Johnson, our friend and colleague. He was a lovely man, always positive, supportive and funny; a highly skilled and valued member of our great road crew,” the band said on its website. ”We will miss him very much. Our thoughts and love are with Scott’s family and all those close to him.”

Tony Vella, spokesman for the Toronto police, told reporters that a 45-year-old man who was hospitalized with a head injury was improving, while the other crew members injured were treated at the scene.

“The one thing that we’re going to be doing is working closely with the Ministry of Labour, trying to determine exactly how that stage came down, and we’re urging any witnesses that were in the area to come forward,” Vella said at an early evening press conference on the grounds. “It’s going to take us a large amount of time to determine exactly what occurred.” He urged witnesses to contact Toronto police.

The Live Nation-promoted concert was scheduled to begin with openers Caribou at 7:30 p.m., followed by Radiohead at 8:30. No concert-goers had yet entered the grounds. The weather was sunny, clear and calm.

Read the full story at Billboard.com/Allindstrom