The attack and the victims
On September 21, 2013, attackers entered Westgate Shopping Mall in Nairobi's Westlands district and began a mass-casualty assault that developed into a prolonged siege. The attack was claimed by al-Shabaab. Contemporary statements from President Uhuru Kenyatta reported 61 civilians and six members of the security forces dead, a total of 67, with many more injured.
The later Kenyan criminal proceedings used a narrower charge-sheet list containing 62 named deaths. Crime by Region keeps those figures separate because they came from different official contexts: the 67 figure reflects the broader reported toll, while the 62 figure was the set of deaths specifically attached to the prosecution document reviewed by the High Court.
The direct attackers and the later prosecution
The four direct attackers were reported killed during the security operation. The criminal case that continued for years therefore focused on people accused of helping, conspiring with or supporting the attackers rather than on the gunmen themselves.
Four suspects were initially arraigned in November 2013. The long case ultimately centered on Mohamed Ahmed Abdi and Hassan Hussein Mustafa. A third defendant, Liban Abdullah Omar, was acquitted in October 2020 for lack of evidence. His later disappearance after release is a separate unresolved matter and is not treated here as proof of any crime by another person.
The 2020 convictions and sentences
In October 2020, the trial court found Abdi and Mustafa guilty of conspiracy to commit a terrorist act. Abdi also faced a separate conviction involving possession of material connected to terrorism. Both received 18-year sentences on the conspiracy count, while Abdi received an additional 15-year sentence on the possession count.
Reporting at the time also described convictions on a support-related count. That part of the trial judgment matters because it was later revisited on appeal, and the final appellate posture is more nuanced than a simple statement that every 2020 conviction was upheld.
The 2024 High Court appeal
On June 28, 2024, Justice Grace Nzioka delivered judgment in the consolidated High Court appeal. The High Court upheld the central conspiracy convictions and the sentences imposed for those offences. It also upheld Abdi's separate conviction and sentence for possession of an article connected with a terrorism offence.
The High Court, however, acquitted the appellants on the charge of knowingly giving support to the commission of a terrorist act. That means the most accurate current summary is not that the entire 2020 judgment survived unchanged. The core conspiracy convictions remained in force, while one distinct support count did not.
Why the case is classified as adjudicated
The Westgate attack itself is not unresolved as to the existence of the event or the identity of the direct attacking group. The later prosecution also produced convictions that survived a High Court appeal in material part. For that reason, the file is placed under Solved / Adjudicated.
That classification does not suggest that every question surrounding the attack, the security response or every possible participant was answered in court. It records a narrower proposition: the direct attackers were identified and died during the siege, and two alleged facilitators received convictions that remained in force after the 2024 High Court judgment.
Timeline
September 21, 2013: the attack begins at Westgate Shopping Mall in Nairobi.
September 24, 2013: Kenyan authorities announce the siege is over; President Kenyatta reports 61 civilians and six security personnel killed.
November 4, 2013: several suspects are arraigned in the terrorism case that later reaches the High Court on appeal.
October 7, 2020: Mohamed Ahmed Abdi and Hassan Hussein Mustafa are convicted; Liban Abdullah Omar is acquitted.
October 30, 2020: Abdi and Mustafa receive prison sentences for conspiracy-related terrorism offences; Abdi receives an additional sentence on a separate possession count.
June 28, 2024: the High Court upholds the core conspiracy convictions and sentences, upholds Abdi's possession conviction, and sets aside the separate support conviction.
August 27, 2026 review: no later judgment overturning the remaining convictions was located in the sources reviewed for this page.
Current status
The case is classified Solved / Adjudicated. The 2013 attack caused a reported 67 deaths overall. Two men later convicted in connection with the conspiracy continue to have core convictions in force after the June 2024 High Court appeal, while a separate support count was overturned.