FILE – This Jan. 14, 2015, file photo made available by the Butler County Jail in Hamilton, Ohio, shows Christopher Lee Cornell of Green Township in suburban Cincinnati. The sentencing of Christopher Lee Cornell, accused of plotting to attack the U.S. Capitol in support of the Islamic State group, has been rescheduled to Monday, Dec. 5, 2016, after he pleaded guilty Aug. 1, 2016, to three federal charges stemming from his Jan. 14, 2015, arrest. A car-and-knife attack at Ohio State University on Monday, Nov. 28, 2016, is the latest in a series of cases involving young men who apparently became radicalized in the heartland state. (Butler County Jail via AP, File)

FILE – This Jan. 14, 2015, file photo made available by the Butler County Jail in Hamilton, Ohio, shows Christopher Lee Cornell of Green Township in suburban Cincinnati. The sentencing of Christopher Lee Cornell, accused of plotting to attack the U.S. Capitol in support of the Islamic State group, has been rescheduled to Monday, Dec. 5, 2016, after he pleaded guilty Aug. 1, 2016, to three federal charges stemming from his Jan. 14, 2015, arrest. A car-and-knife attack at Ohio State University on Monday, Nov. 28, 2016, is the latest in a series of cases involving young men who apparently became radicalized in the heartland state. (Butler County Jail via AP, File)

CINCINNATI (AP) — Authorities are investigating terrorism as a possible motive in the car-and-knife attack on the Ohio State University campus, the latest in a series of cases involving young men who apparently became radicalized in the heartland state.

They are still piecing together information on the activities of Abdul Razak Ali Artan, the Ohio State student killed Nov. 28 by a police officer after he ran his car into others and began slashing with a butcher knife. Among other recent cases that left people close to the suspects stunned, one man has been sentenced to 20 years in prison, another will be sentenced Monday and another was arrested last month.

Their cases have similarities, but also differences, underscoring the challenges to understanding what causes someone to embrace Islamic State calls to violence and how to spot homegrown terrorists.

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“The fact is, anybody can be a terrorist,” said James Forest, director of the Center for Terrorism and Security Studies at the University of Massachusetts-Lowell.

The professor said research has shown a broad spectrum for how long it takes someone to become radicalized. Someone living a seemingly normal life can be “derailed” in a matter of days or weeks.

Citing Artan, whose act apparently had little foreshadowing, Forest said: “How could you identify this person on the street as a potential threat?”

Christopher Lee Cornell, 22, faces sentencing Monday for a plot to assault the U.S. Capitol in support of the Islamic State group. Munir Abdulkader, 22, of the Cincinnati suburb of West Chester Township, was sentenced Nov. 23 to 20 years for an IS-involved plot to kill a military veteran and attack a police station.

In Columbus, Aaron T. Daniels, 20, was arrested in early November at the airport on his way, authorities said, to fly to Libya to fight for the Islamic State.

A look at the recent cases:

THE ALLEGED PLOTS

Cornell wanted to go into the Capitol building during President Barack Obama’s 2015 State of the Union address and shoot the president and others including members of Congress, according to court documents.

Abdulkader wanted to behead a military veteran while taping for a propaganda video, then storm a police station with guns and Molotov cocktails.

Daniels planned to go to Libya to fight to help establish an Islamic State caliphate there, prosecutors have said.

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BACKGROUNDS

Artan was born in the eastern African nation of Somalia, lived with his family seven years in Pakistan and resettled with them in Dallas in 2014 and then Columbus. He was raised as a Muslim. He graduated with honors from Columbus State Community College, and was in his first semester at Ohio State.

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Cornell is a Cincinnati-area native who lived with his parents and brother in a Green Township apartment. After graduating high school, he began identifying as a Muslim; growing his beard long, wearing traditional garb and calling himself Raheel Mahrus Ubaydah.

Abdulkader was born in the tiny east African nation of Eritrea. Raised in suburban Cincinnati as a Muslim, he studied chemistry at Xavier University.

Daniels had graduated from Early College Academy, after attending an alternative high school in Columbus. His mother told The Columbus Dispatch the family wasn’t Muslim, but he had become interested in Islam years ago.

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INFLUENCES

Artan reportedly posted on Facebook about the treatment of Muslims, such as the killing of minority Muslims in the southeast Asian nation of Myanmar, and warning that the United States should leave their countries alone. Investigators say they haven’t yet found any direct connection to the Islamic State extremists. “We only believe he may have been inspired” by the group, said FBI special agent Angela Byers. Artan also might have been influenced by Anwar al-Awlaki, a U.S.-born cleric with a leadership role in al-Qaida before dying in a 2011 U.S. drone strike in Yemen, Byers said.

Cornell’s attorneys say he self-radicalized and lived a fantasy life on his computer, reading ISIS propaganda and conspiracy theories online. They say he was steered in his violent plotting by an FBI confidential informant.

Abdulkader began posting messages of support for extremists on social media in 2014, and communicated with Junaid Hussain, an IS recruiter reported killed last year in Syria in a U.S. drone strike. Authorities say Hussain helped him develop his plot, although his attorney also blamed an FBI confidential informant for pushing him.

Daniels began in 2015 posting social media messages in support of jihad and insurgency in Afghanistan and against Russian-Iranian involvement in Syria, federal authorities said. They said Daniels was encouraged by an Islamic State recruiter, Abu Isa Al-Amriki, who was killed in May by an airstrike in Syria. An undercover agent helped intercept Daniels, authorities said.

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OTHER FACTORS

Artan told the OSU student newspaper The Lantern at the start of the school year that he was concerned about potential reactions to praying in public. “I’m a Muslim, it’s not what the media portrays me to be,” he said. Neighbors described him as friendly.

Cornell’s attorneys say he was lonely and depressed, immature and had mental issues that might have caused him to distort reality.

Abdulkader’s defense said he was thoughtful, but quiet and shy, with a limited network of social influences.

Daniels’ mother said her son was hearing voices and told her that co-workers were calling him the devil in Arabic, according to the court filings. His attorneys are seeking court-approved mental health counseling and treatment.

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Seewer reported from Toledo. Associated Press writer Mark Gillispie contributed in Cleveland.

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Follow Dan Sewell at http://www.twitter.com/dansewell

For some of his other recent stories: http://bigstory.ap.org/content/dan-sewell