LARVIK, Norway -- The trail in the investigation of the deadly attack on a Kenyan shopping mall last month leads all the way to Scandinavia, where the Norwegian police have identified a man who may have been among the assailants.
Investigators are questioning relatives and friends of Hassan Abdi Dhuhulow, 23, a Norwegian citizen born in Somalia, to try to determine whether he was one of the four militants captured on surveillance footage inside the mall in Nairobi, the Kenyan capital, calmly killing shoppers on a Saturday afternoon.
His sister, who spoke on the condition of anonymity, said in an interview here in Larvik, where Mr. Dhuhulow grew up, that officers from the Norwegian security police had asked her whether her brother had placed calls from Nairobi, including from the Westgate mall, during the siege. She said that he had not and that the family was unaware of any role he might have played in the attack.
"My mother and father and me, we don't even know if he is dead or alive," she said. "We are waiting for the whole issue to become clearer."
A spokesman for the Norwegian Police Security Service, Martin Bernsen, said investigators were also unsure whether Mr. Dhuhulow was still alive. Several explosions and a fire at the mall have made it hard to distinguish between the remains of the victims and those of the attackers. The authorities have been unable thus far to identify any of the militants among the bodies pulled from the rubble.
Johansen Oduor, the chief Kenyan government pathologist, said that remains believed to belong to three of the attackers had been pulled from the rubble on Thursday and taken to the Nairobi City Mortuary, but that identification would probably require advanced forensics, including DNA testing. "The bodies are charred," Dr. Oduor said. "There's no face. There's no clothes."
"There are body parts," he said, "and with body parts it's difficult to tell" even how many attackers there were.
The remains were recovered next to AK-47 rifles, the same kind of firearms the attackers were seen carrying in footage from security cameras in the mall. Kenyan security forces do not use that make of rifle. "If you are found next to an AK, most likely you are one of the attackers," Dr. Oduor said.
A man with the same name as Mr. Dhuhulow was arrested in Somalia in connection with the murder of a radio journalist but was freed by a military tribunal for lack of evidence in March.
In 2009, Mr. Dhuhulow began going on what his sister called "long vacations" to Somalia. Contact with the family was sporadic, and she could not remember whether she had last spoken to him last year or the year before. "My brother leads a different life than me," she said.
A family member told the BBC that he had called this summer and said he was in trouble.
The Norwegian Police Security Service said in a statement last week that it had received information that a Norwegian citizen of Somali origin may have been involved in "the planning and execution of the attack" in late September, when militants stormed the mall and killed more than 60 men, women and children. The Norwegians sent investigators to Nairobi to work with Kenyan security services on the investigation.
The Somali militant group known as the Shabab has claimed responsibility for the assault. The Kenyan authorities initially said 10 to 15 assailants had been involved. Officials with knowledge of the investigation now say the number was no more than six and may have been as few as the four captured on the surveillance tapes.
Kenyan officials released four names, but none of them was Mr. Dhuhulow's; officials with knowledge of the investigation said later that the released identities were believed to be noms de guerre, not birth names.
As recently as last week, investigators were still referring to the attackers as "pink shirt, white shirt, black shirt, blue shirt," based on the clothes they were seen wearing in surveillance footage. Mr. Dhuhulow is believed to be the militant in the black shirt who was filmed in a grocery store, his left pant leg soaked in blood.
Norway has increasingly come into focus as investigators from Kenya, the United States, Norway and elsewhere work to piece together the Shabab's international network. Navy SEALs staged an unsuccessful raid in the Somali coastal town of Baraawe this month to try to capture a Shabab planner, Abdikadir Mohamed Abdikadir, also known as Ikrima. Mr. Abdikadir is believed to have lived in Norway as an asylum seeker between 2004 and 2008.
"When we investigate one Norwegian involved, we are interested in his connections," Mr. Bersen said.
More and more video footage of the attack has leaked out in the weeks since the siege ended. Disturbing new clips released on Thursday showed terrified shoppers running for their lives while the killers stalked them, leaving victims in pools of blood on the mall floors.
Mr. Dhuhulow's sister said the police believed that he had called the family from inside the mall, a version of events she contested. "They think so because it said so in some Kenyan newspaper," she said. "They do not have this information confirmed. He certainly did not call anyone in the family; we would have known if he did."
Larvik is a small city on the Norwegian east coast south of Oslo, with around 43,000 residents. Mr. Dhuhulow attended Thor Heyerdahl High School here until 2009, according to Stine Indhal, an administrator at the school, concentrating on natural sciences and mathematics.
Norway's TV2 reported that Mr. Dhuhulow was active in an online forum linked to the Shabab and posted photographs of "martyrs" killed in Bosnia. On one site, TV2 reported, he used a suicide bomber as his profile picture.
The local newspaper Ostlandsposten quoted an unnamed former classmate as saying that in high school he was surfing "odd Web sites," including ones about "liquidating" American soldiers.
The newspaper reported that several former classmates recognized him in the video footage from both his gait and his hand gestures. "I remember him as fanatical when it came to Islam," a classmate told the newspaper. "I remember him reading a lot of Web sites about Allah and about his religion."
The Norwegian state broadcaster NRK quoted police sources as saying that the Police Security Service had kept track of Mr. Dhuhulow since high school and that he was in contact with central figures of a Norwegian-based Islamist group, Profetens Ummah, or the Prophet's Ummah.
Kristina Sandbrekkene Olsen, 22, who went to the school at the same time as Mr. Dhuhulow but did not remember him specifically, said she had many Muslim friends from Chechnya and Kosovo as well as Somalia. "Terrorism was never a topic among any of us, and religion wasn't a big subject, either," Ms. Olsen said.
According to his sister, Mr. Dhuhulow stayed in touch with the family in Norway only occasionally after moving to Somalia. "It's still hard to believe," she said. "I can't bear the thought of this actually being true. It's just too much come to terms with."
Henrik Pryser Libell reported from Larvik, and Nicholas Kulish from Nairobi, Kenya.
This article originally appeared in The New York Times. First Published October 18, 2013 2:01 PM