NAIROBI, Kenya (AP) — A magistrate's court in Kenya has ruled that three men must stand trial on charges they were involved in a deadly attack on a Nairobi shopping mall in 2013.

The magistrate said Monday he was satisfied with prosecutors' evidence linking the three suspects to the days-long siege of Westgate Mall in which 67 people were killed.

A fourth suspect was freed for lack of evidence.

The Somali Islamic extremist group al-Shabab claimed responsibility for the attack that shocked Kenyans and horrified the world.

Since 2011 the rebel group, which is linked to al-Qaida, has vowed retribution on Kenya for sending troops to Somalia.