Kenyan officials and media reports say a Norwegian-Somali man is believed to have helped carry out the attack on a Nairobi mall that killed over 60 people.
The BBC reported that Hassan Abdi Dhuhulow was identified as one of several gunmen in security footage from the attack on the Westgate Mall.
A Kenyan security official told the Associated Press one of four men seen in the footage is a Norwegian-Somali with a similar name.
Kenyan authorities previously released the name of four other militants they say were involved the attack. All were killed.
The fighters stormed the upscale mall on September 21, executing scores of people and setting off a standoff with security forces that lasted for four days.
The Somali insurgent group al-Shabab claimed responsibility, saying the attack was revenge for Kenya sending security forces into Somalia to kill its fighters.
Al-Shabab, whose name in Arabic means "the guys," is fighting to impose their strict version of Islamic law on Somalia. It has threatened more attacks in Kenya.