Who is the leader of local extremist group behind Sri Lanka attacks

The purported leader of the extremist group blamed for the Easter attacks in Sri Lanka that killed over 300 people began posting videos online three years ago, faith leaders said Tuesday. 
Much remains unclear about how a little-known group called National Thowfeek Jamaath carried out six large nearly simultaneous suicide bombings striking churches and hotels on Sunday.
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However, warnings about growing radicalism in this island nation off the coast of India date to at least 2007, while leaders say their repeated warnings about the group and its leader drew no visible reaction from officials responsible for public security.  
"Some of the intelligence people saw his picture but they didn't take action," said NM Ameen, the president of the Muslim Council of Sri Lanka. 
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Tension coursed through Colombo on Tuesday as the military took on emergency war-time powers, allowing them to conduct warrantless searches and detain suspects for up to two weeks before a court hearing. 
Such powers haven't been invoked since Sri Lanka's bloody civil war, when people feared that unclaimed bags or debris could hide a bomb. On one commuter train Tuesday morning, panicked passengers shouted over one unclaimed piece of luggage until its owner was found.
Authorities have blamed National Thowfeek Jamaath for the attack. Its leader, alternately known as Mohammed Zahran or Zahran Hashmi, became known to religious leaders three years ago for his incendiary speeches online.  
Zahran's name was on one intelligence warning shared among Sri Lankan security forces, who apparently even quietly took their growing concerns to international experts as well.
Anne Speckhard, the director of the International Center for the Study of Violent Extremism, said a Sri Lankan intelligence official approached her at a conference in February with a surprising question. She was worried about what she described as a violent, homegrown group that "would just disappear" when the government tried to crack down on them. 
"The intel person kind of came up to me and said, 'You know, we're kind of worried about this new group and there's some activity going. What do you think?'" Speckhard told The Associated Press on Tuesday. "It just kind of blows my mind that's who it was."  
As far as the planning, Speckhard noted that Sri Lanka was "a part of the world that developed suicide vests" during the civil war against the Tamil Tigers, a secular, a group that once was the world's top suicide attacker. But the style of Sunday's attacks, targeting churches on Easter and hotels frequented by foreigners, followed that of Al Qaeda and Daesh.  
"It is a simple attack that is well thought out," Speckhard said. "I do believe well thought out is a product of being in touch with someone from the outside." 
That's a feeling shared by the Austin, Texas-based private intelligence firm Stratfor. 
"The degree of sophistication in the making of the bombs indicates that the attackers did in fact have help from outside Sri Lanka, which could have come via coordination with external militant groups such as Al Qaeda or Daesh, from Sri Lankan fighters returning from battlefields in Iraq and Syria, or from a combination of the two," a Stratfor analysis said Tuesday. "Clarity on the nature of such networks, however, will have to wait for the emergence of more details about the attacks."  
Daesh claimed responsibility for the Sri Lanka attack via its Aamaq news agency on Tuesday, but offered no photographs or videos of attackers pledging their loyalty to the group. Such material, often showing suicide bombers pledging loyalty to the group before their assaults, offer credibility to their claims.