Johannesburg - Police were unsure on Wednesday of the motive behind the explosion at Czech businessman Radovan Krejcir's business premises which claimed the lives of two people.
“At this stage the motive is unknown, but investigators have taken statements from a few people,” Brigadier Neville Malila told reporters on the scene.
Krejcir was not considered a suspect at this point.
“Investigators took a statement from him last night [Tuesday] and at this stage he is not a suspect. They will be able to get hold of him if it is needed,” said Malila.
The device went off late on Tuesday afternoon at Krejcir's Money Point gold and diamond exchange office, next to the Eastgate shopping centre in Bedfordview, on the East Rand.
Five people were injured. Three were still in hospital, with one believed to be in a critical condition.
Police helicopters landed at the scene on Wednesday morning.
A forensic expert said the building's roof had collapsed because of the magnitude of the blast.
Speaking on condition of anonymity, he said police were still trying to establish what kind of explosive was used.
Malila said police could not reveal the names of the deceased as they had not yet been identified.
The type of device used was not known, as crime scene experts were still combing the scene.
Malila said the evidence would be taken to a laboratory for analysis.
He said the matter was being investigated by detectives from the Hawks and the national and provincial police.
Sapa