Source: Store in besieged Kenyan mall run by attackers or associates
September 27, 2013 -- Updated 1940 GMT (0340 HKT)
- NEW: Possible Al-Shabaab Twitter account warns Nairobi the attack was only "Act 1"
- Source: Investigators link a store rented in the past year to the attackers
- Despite 8 in custody, there's rising concern that some of the attackers escaped
- At least 67 people are known dead; as many as 61 remain unaccounted for
Nairobi, Kenya (CNN) -- To anyone shopping at Nairobi's Westgate Mall, it would likely have seemed just another store.
But according to a Kenyan intelligence official, the small shop concealed an ominous secret. It was rented by the Al-Shabaab terrorists, or their associates, who within a year would carry out an attack on the upscale shopping mall.
The information -- revealed Friday to CNN by the source, who is close to the investigation into the attack -- suggests the Somalian terror organization had been planning the operation at least that long.
How the team of terrorists got their weapons and explosives into the mall without notice is a central part of the investigation into the attack, which left at least 67 people dead and parts of the upscale mall in ruins.
The Kenya Red Cross said Friday that 61 people remain unaccounted for. Some could be buried in the rubble of the partially collapsed mall.
Relatives of Johnny Mutinda Musango, 48, weep after identifying his body at the city morgue in Nairobi, Kenya, on Tuesday, September 24. Musango was one of the victims of the Westgate Mall hostage siege. Kenyan security forces were still combing the mall on the fourth day of the siege by al Qaeda-linked terrorists.
Photos: Kenya mall attack
A woman shouts during a special prayer at the Legio Maria African Mission church in Nairobi, Kenya, on Sunday, September 29, for the victims of the Westgate Shopping Mall shooting.
Photos: Kenya mourns mall shooting victims
Bergen: Unlikely women were attackers
Heroism during a moment of terrorism
At least five of the terrorists also died before Kenyan forces were finally able to bring the siege to an end on Tuesday. The terrorists stormed the building Saturday.
Read: Mall attack timeline
On a Twitter account believed to be run by Al-Shabaab, the group promised more attacks to come.
"The mesmeric performance by the #Westgate Warriors was undoubtedly gripping, but despair not folks, that was just the premiere of Act 1," according to a tweet posted Thursday.
CNN could not confirm the authenticity of the tweet, but CNN terrorism analyst Paul Cruickshank said the account, which has also posted links to statements from Shabaab leader Mukhtar Abu Zubayr, appears to be legitimate, even if not "100% authenticated."
Several Twitter accounts attributed to Al-Shabaab have been shut down in recent days, likely for violating the company's rules against promoting violence in tweets.
While Kenyan Interior Minister Joseph Ole Lenku said Friday that eight suspects are being held for questioning in the attack, authorities are increasingly concerned that some of the attackers managed to escape alongside fleeing civilians in the aftermath of the initial attack, U.S. law enforcement officials told CNN.
On Thursday, a Kenyan counterterrorism source told CNN that one of the suspects is an injured Kenyan who was being evacuated when a machine gun magazine fell out of his pocket, leading to suspicion he was among the automatic-weapon toting terrorists who roamed the mall killing civilians. He is being held in a military hospital, the source said.
READ: Source: Kenya mall attack suspect eyed after ammunition fell out of his pocket
Among the suspects are three people picked up near the Ugandan border, the Kenyan official who revealed information about the mall store told CNN.
READ: More U.S. Marines fortify Nairobi embassy security
CNN's Michael Pearson reported and wrote from Atlanta; Nima Elbagir reported from Nairobi; CNN's Neda Fashbaf also contributed to this report
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Kenya mall attack
October 17, 2013 -- Updated 1355 GMT (2155 HKT)
As they strolled through the mall, guns strapped to their torsos, the attackers chatted on cell phones while they sprayed bullets at shoppers.
October 22, 2013 -- Updated 1132 GMT (1932 HKT)
A leaked video footage from inside has sparked anger amid claims that it shows soldiers looting from stores as they hunted for the gunmen.
October 10, 2013 -- Updated 1908 GMT (0308 HKT)
Elaine Dang pretended to be dead, and maybe because she did, she is alive to tell her story. She moved away from the crowd because she thought it would be most vulnerable.
October 7, 2013 -- Updated 1029 GMT (1829 HKT)
U.S. Navy SEALs entered the southern Somalia stronghold of Al-Shabaab, the group behind the Kenyan mall attack, in a mission targeting one of its leaders.
September 27, 2013 -- Updated 1940 GMT (0340 HKT)
Investigators have determined the attackers or their associates rented and operated a small store in the mall a year before the Kenya mall attack.
September 26, 2013 -- Updated 2045 GMT (0445 HKT)
Propped up by strangers, a woman wails outside Nairobi's main city morgue, unable to control her grief.
September 29, 2013 -- Updated 1701 GMT (0101 HKT)
Loved ones mourn the lives lost in the Westgate mall attack. Dozens of civilians and 6 security officers died in the four-day attack.
September 24, 2013 -- Updated 2058 GMT (0458 HKT)
The attack at Westgate mall lasted for four deadly days, with store-to-store siege.
September 27, 2013 -- Updated 0038 GMT (0838 HKT)
There is evidence that replicating the 2008 Mumbai, India, attacks has become a major priority for al-Shabaab and al Qaeda.
September 28, 2013 -- Updated 1336 GMT (2136 HKT)
Twenty men are engaged in fiery debate on a sidewalk near Nairobi's Westgate mall, where terrorists stormed the shopping center and killed at least 67 people.
September 27, 2013 -- Updated 2128 GMT (0528 HKT)
It was the first major terrorist attack in history in which the group that mounted the operation used Twitter to announce to the world it was responsible.
September 25, 2013 -- Updated 0242 GMT (1042 HKT)
Photos from the attack as it happened.
September 24, 2013 -- Updated 1753 GMT (0153 HKT)
A safe distance from Nairobi's Westgate Mall, several Kenyans stare through a stand of trees at the site of one of the nation's worst terrorist attacks.
September 26, 2013 -- Updated 1459 GMT (2259 HKT)
British-born Samantha Lewthwaite was once seen as a kind of victim of the July 2005 London terror attacks -- the pregnant wife of one of the suicide bombers.
September 26, 2013 -- Updated 0222 GMT (1022 HKT)
Some answers may be revealed in blood-stained halls or deep in the rubble of Nairobi's Westgate Mall. Others may never be known.
September 27, 2013 -- Updated 0125 GMT (0925 HKT)
The Westgate mall's parking deck collapsed leaving a crater full of destroyed and burned cars in Narobi, Kenya.
September 24, 2013 -- Updated 1138 GMT (1938 HKT)
Of all al Qaeda's affiliated groups, the Somali terrorist organization Al-Shabaab has over the years had the deepest links to the U.S.
September 23, 2013 -- Updated 1440 GMT (2240 HKT)
It's hard to imagine a softer target than an enclosed, easy-to-enter space with large numbers of civilians milling about.
September 23, 2013 -- Updated 1648 GMT (0048 HKT)
Al-Shabaab, an al Qaeda-linked militant group based in Somalia, is believed to be responsible for the deaths of aid workers and peacekeepers
September 24, 2013 -- Updated 2115 GMT (0515 HKT)
What the mall looked like before the attack.
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