Nairobi– At least six people have been singled out for their involvement in last month’s Westgate mall attack -and that number is expected to double once the investigation is complete, a senior Kenyan government official said.Previously, a spokesman for the Kenya Defense Forces identified four terrorists who took part in the mall attack, which left at least 67 people dead. Those four are Khattab al-Kene, an American Somali; Abu Baara al-Sudani, from Sudan; Omar Nabhan, from Kenya.

Kenya’s Counter-Terrorism Office said Nabhan was related to former senior al Qaeda in Somalia operative Saleh Ali Nabhan, who was killed in a U.S. strike in southern Somalia in 2009. Both men were from Mombasa, Kenya.

The four died when the part of the mall they were in collapsed, Maj. Emmanuel Chirchir said. The charred bodies of the four are undergoing DNA verification.