Reporting from Washington and Portland, Ore. — Friends called him "Mo," and one remembered him as the class clown. He drank beer, followed the Portland Trail Blazers and liked hip-hop music. He sometimes worshipped at a local Muslim center but wasn't devout.
And for a high school physics project, he told the class how to operate a rocket-propelled grenade launcher.
Mohamed Osman Mohamud — the 19-year-old Somali American accused of trying to explode a powerful car bomb amid throngs of people at a holiday ceremony Friday night in downtown Portland, Ore. — appears a mix of typical teenager and aspiring jihadist, according to former classmates, neighbors and court documents.
Authorities said the bomb was a deliberate dud supplied by the FBI, and no one was injured. Federal agents arrested Mohamud on the spot. He is scheduled to be in federal court Monday on a charge of attempted use of a weapon of mass destruction.
In a possible reaction to the purported bomb plot, federal officials said an arson fire early Sunday ravaged part of a two-story Islamic center in Corvallis, Ore., that Mohamud occasionally attended.
The pre-dawn blaze at the Salman Al-Farisi Islamic Center, a fixture for 40 years in the university town, destroyed the main office. It did not affect the worship areas, said Yosof Wanly, imam at the center.
FBI officials said they didn't know if the mosque was targeted as revenge for the alleged plot to kill revelers attending Portland's annual Christmas tree-lighting ceremony. The bureau offered a $10,000 reward for information that leads to the arrest and conviction of whomever set the fire.
"We have made it quite clear that the FBI will not tolerate any kind of retribution or attack on the Muslim community," said Arthur Balizan, special agent in charge of the FBI in Oregon. "We are working very closely with the leadership at the mosque. We will find the person responsible for this attack and bring the full force of the federal justice system to bear."
Both the alleged bomb plot and the arson have stunned Portland, and raised fears of further backlash against Muslims.
Officials said Mohamud was born in 1991 in Mogadishu, capital of Somalia, at the start of the African country's civil war.
He and his parents, Mariam and Osman Barre, came to America when he was 5 as part of a diaspora that brought tens of thousands of Somali refugees to U.S. cities. About 6,500 Somalis are said to live in the Portland area.
Few details were available about Mohamud's early years. It wasn't known when he became a naturalized American citizen. Neighbors said he had a younger sister, Mona, and a younger brother.
In 2008, the family settled in the newly built Merlo Station Apartments, which provides housing for low-income families. The three-story complex sits between a light-rail station and the Tualatin Hills park and recreation center in Beaverton, on the west side of Portland.
The upscale suburb could not be more different from war-torn Mogadishu.
Beaverton boasts more than 100 parks, plus winding hiking trails and miles of bike paths. Ski slopes and beaches are just more than an hour away. Residents are overwhelmingly white and Asian.
"His mom stated to me once that she loved America," said Stephanie Napier, a former neighbor. "They all moved here so they could go to school."
She remembered Mohamud as quiet and polite. "He would always wave hello."
Napier's son, Tyler, 17, said Mohamud "had his own little social group, mostly Somali kids or Middle Eastern kids," he said.
As a boy, Mohamud attended Markham Elementary School and Jackson Middle School, both in southwest Portland. Jackson's arts-based curriculum was "inspired by the vision of the great American composer, Leonard Bernstein," according to its website.
He next attended Wilson High School but soon transferred to Westview High School, just down the street from the Merlo Station complex. He joined the school's literary magazine, played a fierce game of pickup basketball and graduated in June 2009.
It was at Westview that Mohamud detailed a rocket-propelled grenade launcher for his physics class, former classmates said. One student, Andy Stull, told Portland's NewsChannel 8 that he and Mohamud had fought over a messy locker.
"The main thing was the way he said he hated Americans," Stull said. "It was serious. He looked me in the eye and had this look in his eye, like it was his determination in life — 'I hate Americans.' "
Stull said he was frightened enough to tell school counselors. School officials could not be reached Sunday.
Another former classmate said Mohamud sometimes joked about being a terrorist, and that he had sent a peculiar text message this month.
"He texted me asking if I knew of any places where he could shoot guns off where nobody would hear," said Alex Masak. "I didn't think much of it. …I assumed he was just messing around with his friends."