"As far as I can see, most had already been killed up there on the bridge," he said. "It looks like the driver was acting intentionally."
But he later rolled back on the suggestion in comments to another newspaper, Länstidningen Södertälje. He suggested that the driver of the car - who has not been specified by police - lost concentration while squeezing past the queueing cars.
"My theory is that he was inattentive for some reason, perhaps talking on a mobile phone or turning round to the others in the car, and he didn't see the barrier in time," Berglund said.
The band, made up of four friends from their hometown of Warrington, Cheshire, were guitarist and vocalist Kristian Leonard, 20; guitarist River Reeves, 19; bass player Tomas Lowe, 27, and drummer Jack Dakin, 19. Manager Craig Tarry, 32, was the fifth person in the hire car.
In the week after the accident, the band reached number one in the iTunes chart following a social media campaign backed by Manchester music legends Liam Gallagher, from the band Oasis, and Tim Burgess from The Charlatans.