RUSSAIFA, Jordan (AP) -- On his last day as an ordinary teenager, Abdullah Siddeh kept to his daily routine: He filled in for his father at the small family grocery in the afternoon, asked his mother at home about dinner and then played soccer with friends at the nearby high school.
After the game, the 17-year-old slipped out of his hometown in central Jordan.
Six months later, his father Mohammed got a phone call from Syria. His son had blown himself up in a rebel attack on a police station in Syrian capital of Damascus, the unknown man on the line told him.
Mohammed said he asked the man how he could bring his son's remains home for burial.
The reply: "There is no body."
With Syria now the latest conflict zone where suicide attacks have become a key tactic, AP reporters interviewed the families of Abdullah and another foreign suicide bomber in Syria, 22-year-old Mohammed Zaaneen from the Gaza Strip who died in September, to learn more about their motives.
Experts say there's no "typical" bomber. But the stories of these two individuals offer a glimpse into how Islamic militant groups have reached across borders to instill some disaffected youth with the jihadi ideology behind their most horrific tactic.
Over the past decade, the use of suicide bombers has evolved. In the 1980s and 1990s, the tactic was used mainly in nationalist causes -- Palestinians, for example, unleashed it in their fight against Israel, as did mainly Hindu Tamils in their fight against Sri Lanka's government.
But the wars in Afghanistan and especially Iraq transformed it. Suicide attacks became more central to militants' way of fighting and took on a transnational aspect. Militant groups used jihadi ideology honed by al-Qaida and other Islamic extremists to draw foreign recruits into the fight, in the name of defending both land and religion.
More than 1,300 attacks have been carried out in Iraq since the U.S.-led invasion in 2003, out of more than 3,100 suicide bombings worldwide since 1980, according to data collected by the Chicago Project on Security and Terrorism.
The newest jihad battleground, Syria, has inherited the mantle, as al-Qaida-linked groups eclipse nationalist rebels as the most powerful forces in the fight against President Bashar Assad. The Chicago Project documented almost two dozen suicide bombings there in 2012, and dozens have taken place this year.
It's not the only new front. In Egypt's bloody insurgency of the 1990s, Islamic militants did not carry out suicide attacks. Now they do: The tactic has been used several times the past few months against troops and security forces in the Sinai Peninsula and in Cairo in a nascent insurgency sparked by the July ouster of Islamist President Mohammed Morsi.
For both Abdullah Siddeh of Jordan and Mohammed Zaaneen from the Gaza Strip, ideology was a powerful motivator, according to their families. Before joining rebel fighters in Syria, they embraced Jihadi Salafism, a strain of the puritanical Salafi stream of Sunni Islam.
Jihadi Salafism's doctrine of global holy war forms the ideological basis for the al-Qaida terror network, preaching that committed Muslims must fight non-believers everywhere. They include non-Sunnis -- like Assad, a member of the Shiite-offshoot Alawite sect -- among the infidels.
Abdullah grew up in a mainstream Muslim family in Russaifa, a drab industrial city of 300,000 where jobs are scarce and teens have limited options.
Raed Khater, the librarian at Abdullah's high school, said students either take up smoking and chasing girls or become religious. The vast majority of high school seniors fail university matriculation exams, he said.
Abdullah became intensely religious as a young teen, a cause of friction in the family, said his oldest brother, 22-year-old Afif, who is not observant. Abdullah would object to Afif watching TV programs featuring women or popular music, but Afif's opinion usually prevailed because he contributes to the family by selling scrap metal.
After the Syrian conflict turned more violent, Abdullah dropped hints about martyrdom and wanting to fight Assad, his father said. Abdullah sometimes raided the family refrigerator to give food to Syrian refugees streaming into Jordan.
His last day in Russeifa, Dec. 20, was a Thursday, and Abdullah was observing a dawn-to-dusk religious fast, as he did twice a week.
When he returned home, he asked his mother to prepare something delicious for the evening meal and went off playing soccer. He never returned home for the meal.
Two days after his disappearance, he called from Syria, saying he was fine.