Lebanese authorities say they have identified the two men who launched a double suicide attack on the Iranian embassy this week which killed 25 people in Hezbollah's southern Beirut bastion.
Relatives of one of the men said he was a supporter of Al-Qaeda and Sheikh Ahmed Assir, a radical Sunni preacher in southern Lebanon who has been on the run since his supporters clashed with Lebanese troops in the summer, killing 17 soldiers.
The embassy attack was claimed by an Al-Qaeda-affiliated group that said it was targeting the Iran-backed Lebanese Shiite movement Hezbollah, which is fighting alongside President Bashar al-Assad's troops against Sunni-led rebels in neighbouring Syria.
Both suicide bombers were identified by DNA testing, the army and a judge said, one of them after his father came forward when photos of the suspects were published.
The test on Adnan Abu Dahr showed that human remains at the scene belonged to his son, Mouin Abu Dahr, who was identified as one of two attackers, the judge was quoted by the National News Agency as saying.
The army confirmed that the younger Abu Dahr, from the southern Sunni-majority town of Sidon, was one of the suicide attackers.
A Facebook page apparently belonging to Mouin Abu Dahr, which had been taken down by Saturday, expressed support for Al-Qaeda and for Assir, whom he vowed to "avenge" after the clashes with the army.
Assir, also from Sidon, had frequently expressed support for the Syrian uprising and encouraged Lebanese Sunnis to join it.
The army also confirmed that DNA testing showed the second bomber was Adnan Mussa al-Mohammad, a Palestinian who also lived in southern Lebanon and reportedly supported Assir.
The double bombing was the first attack in Lebanon against interests of predominantly Shiite Iran, a key ally of the Syrian regime as it battles a 32-month uprising.
An estimated 120,000 people have been killed in Syria since the revolt began as a series of peaceful protests in March 2011.
A brutal government crackdown on the demonstrations eventually set off a full-blown civil war that has displaced millions of people, including some 800,000 who have taken refuge in Lebanon.
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Tehran is also the key sponsor of Hezbollah, which has dispatched fighters to Syria to aid the regime.
Lebanon's ever-feuding factions have been bitterly divided over the Syrian civil war, and a string of bombings and other attacks have raised fears the conflict could spill over the border.
In Sidon on Saturday, two tanks were stationed near the Abu Dahr home, where neighbours expressed shock that Mouin had carried out the attack.
"He was a polite man who always encouraged me to pray. I did not expect him to commit such an act," Ahmed al-Yaman, who lives across the street, told AFP.
A close friend who asked not to be identified said Mouin became far more religious after a recent trip to Sweden, where he fell under the influence of a radical imam.
"After he returned from Sweden, he started talking about martyrdom and saying his family was not religious enough," the friend said.
After Assir was chased into hiding, the friend remembers Mouin speaking of an injustice against Sunnis and making an ominous vow.
"He said he would commit an act that everyone would talk about."
The mother of the Palestinian suspect, Adnan, was in shock and refused to believe he was one of the bombers, while an uncle linked him to Assir.
"My son was devout and went regularly to the mosque (to pray)... I can't believe he committed this frightening crime," said his mother.
An uncle added that Adnan's father had learned from neighbours that he had been attending gatherings with Assir and had tried to talk him out of getting close to him.
"But he refused and left the house... months ago, and we knew nothing of him until his name was linked" to the Iran embassy attack.