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Kenya military caused Westgate Mall collapse, official says

NAIROBI, Kenya A top-ranking government official tells The Associated Press that Kenya's military caused the massive collapse of three floors during the terrorist siege on Nairobi's Westgate Mall.

When asked Friday if military action against the hostage takers caused the collapse, the official answered: "Yes."

The official also confirmed that Kenyan troops fired rocket-propelled grenades inside the mall, but would not say what was used to cause the collapse. The official insisted on anonymity because he was sharing sensitive intelligence information that has not been publicly released.

The top official's confirmation backs up information given to AP by another official on Wednesday, who said soldiers were responsible for the collapse which created a gaping hole in the mall's roof. That official said fired RPGs caused the collapse.

FBI agents join Kenya mall siege investigation

CBS News correspondent Charlie D'Agata reported on Thursday that a government official believes that the rocket-propelled grenades knocked out a supporting column in Westgate Mall - although a military explosives expert told CBS News that this was probably unlikely.

Four huge explosions rocked the mall Monday followed by dark smoke pouring from the shopping center, the likely time that the floors collapsed. The government hasn't publicly explained what caused the floors to collapse. One official earlier suggested it was caused by a mattress fire inside the Nakumatt department store.

It is believed the collapse of the floors helped to bring an end to the four-day siege at the mall, but it may have killed hostages still inside.

Forensic teams have been at work collecting fingerprints and DNA to identify attackers and victims while ballistics experts have been identifying the weapons used.

The official who spoke on Friday said autopsies on bodies under the rubble will show if those people were killed by the building collapse or had been slain earlier by the terrorists. The official said bodies are expected to be found after excavation of the roof collapse begins.

D'Agata reported on Friday that FBI agents and dozens of other foreign investigators - as many as 50 - are currently inside the mall collecting evidence. There are ongoing fears the mall might be booby trapped, or at the very least strewn with unexploded munitions and grenades.