Forensic investigators on Thursday recovered some body parts and three AK47 rifles from the Westgate Mall terror attack site.
A security officer who is close to the investigation told Xinhua that they believe a human skull and other body parts recovered from the rumble belong to the four terrorists who were killed during the four-day siege after the Sept. 21 attack.
The security officer said they believe there are still more bodies or parts trapped in the rubble, adding that the search might take some weeks.
"We retrieved some human body parts including a skull. We believe these body parts belong to the four terrorists who were killed during the attack," the officer who did not want to be identified told Xinhua by telephone.
He also said a rocket propelled grenade was also recovered from the terror site, adding that bomb experts later detonated the device.
Forensic investigators early this month identified one of the vehicles used by terrorists who stormed the shopping mall and opened fire on shoppers.
The investigators have recovered crucial items in the vehicle and they are providing good and credible leads. Some of the items found in the vehicle include an assortment of illegal weapons.
The human skull was discovered in the rubbles by officials who are doing the recovery and search of bodies at the site almost a month after the attack happened.
"We will continue with the recovery tomorrow (today) but we have made some recoveries. What we discovered today will offer crucial information on the identities of those behind the attack," the security officer said.
Kenyan authorities are currently holding over 40 suspects for interrogation in connection with the Nairobi mall terror attack.
The authorities said security had been stepped up and appealed to city residents to be extra vigilant and take security measures seriously, regardless of their status in society.
The police have also admitted that despite a boost in security the threat remained, urging shopping malls to remain vigilant and to "do more" to prevent attacks.
The authorities have particularly warned against the laxity in the screening of cars for explosives at all shopping malls.