The inquest into the deaths of four men killed in an industrial accident in Great Yarmouth is set to start tomorrow.
Home Office post mortem examinations carried out on Tuesday established that the cause of death was asphyxia due to trauma.
Peter Johnson, 42, Thomas Hazelton, 26, Daniel Hazelton, 30, and Adam Taylor, 28, from Stanton near Bury St Edmunds were killed when digging foundations for an extension at Claxton Engineering in Runham on Friday.
They were working four feet underground when a steel structure collapsed, trapping them.
Senior investigating officer DCI Neil Luckett from the Joint Major Investigation Team said: 'Investigations at the site and elsewhere continue.
'This will be a lengthy and complex investigation and we do not anticipate issuing any further updates at this time.'
The inquest will be opened by a coroner at the Assembly House in Norwich.
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