Five more people are being held in connection with the terrorist attack on the Westgate mall in Nairobi, Kenya, a senior Kenyan government official said Wednesday.

The five are in addition to as many as 11 people taken into custody by Kenyan authorities shortly after the September 21 attack.

They are scheduled to appear in court on Monday, according to the official, who could not be named due to the sensitivity of the case.

Gunmen believed affiliated with the Somalian terror group Al-Shabab stormed the mall at the outset of a four-day standoff that left at least 67 people dead and parts of the center destroyed.

Surveillance video obtained by CNN shows gunmen casually shooting some civilians. They reportedly also tortured some hostages, according to military doctors who saw evidence of severed hands and noses. Some hostages had been hanged, according to the doctors.