By JASON STRAZIUSO
Associated Press

NAIROBI, Kenya (AP) _ A Western official briefed on the Kenya mall attack investigation says the bodies of the attackers have not been found.

Investigators, including FBI agents, are working their way through the collapsed mall rubble following the four-day siege on Westgate Mall that began Sept. 21. At least 67 people died in the attack.

The official said Friday that the attackers’ bodies could be under the rubble but that it’s not yet confirmed. Kenyan officials have said mall security video shows at least four attackers, though there are indications that perhaps two more attackers took part.

The official said the real names of the attackers aren’t yet known. Names released by Kenya‘s military previously are only operational nicknames. The official insisted on anonymity because the information has not yet been publicly released.