Guwahati, July 28 -- Five people, including the owner of an iron casting unit in Assam's Cachar district, have been arrested in connection with the explosion that killed four workers earlier this week, police said on Monday.

The factory owner, Rakesh Kumar Surana, was apprehended in Guwahati on Monday and later taken to Udharbond Police Station in Cachar for further questioning. Investigators have booked him on charges of alleged negligence, accusing him of failing to ensure adequate safety measures at the industrial unit.

Four others, including the factory manager, who had initially been detained following the incident, were formally arrested as the investigation progressed.

Police said a team of forensic experts will examine the site...