A man who as a teenager was seen on surveillance video proclaiming his commitment to jihad was sentenced on Tuesday to 13 years in prison despite his tearful pleas to a judge that he was a disillusioned and immature high school student at the time he plotted to join al-Qaida.

“I am not the monster that the government says I am,” Justin Kaliebe told U.S. District Court Judge Denis Hurley before being sentenced. “I never intended to hurt anyone. That’s not who I am.”

Kaliebe, now 22 years old, also faces 20 years of post-release supervision.

The judge said Kaliebe’s offense “is very serious.”

“He was radicalized to the nth degree,” the judge said. “He was a very dangerous individual. People who engage in this type of activity … must recognize that serious consequences will follow.”

Kaliebe was a 16-year-old high school student who had recently converted to Islam from Roman Catholicism when he landed on the radar of undercover agents on the hunt for would-be radicals on suburban Long Island.

FBI agents and New York City police officers watched him for 18 months before arresting him four years ago after he went to John F. Kennedy International Airport intending to fly to Yemen, where he would join the militant group al-Qaida.

Kaliebe pleaded guilty within a month of his arrest. His sentencing was delayed for four years while the court held hearings into whether he understood the gravity of his crime. He said Tuesday he has renounced Islam, received his high school diploma while in prison and teaches fellow inmates to read.

Kaliebe’s attorney argued he has Asperger’s syndrome, which is on the autism spectrum, and had developmental and psychological issues and a troubled home life.

“He may have committed himself to a violent cause, but he’s not a violent man,” said the attorney, Anthony La Pinta, who pleaded with the judge to “temper justice with mercy.”

The judge, who noted that Kaliebe appeared to be “basically a nice young man,” could have sentenced him to 30 years.

Federal prosecutors asked for a 24-year sentence, conceding that Kaliebe had psychological, physical and emotional issues but arguing a stiff sentence needed to serve as a deterrent to society.

They said the undercover agents interacting with Kaliebe made video recordings of him talking admiringly about Anwar al-Awlaki and Osama bin Laden as leaders who “bore witness to the truth with their blood.”

Just days before Kaliebe’s arrest, he pledged in one of those secretly recorded conversations that he would rather go to prison than abandon his plan to join Islamic militants.

“One of my highest goals in life is to fight with the mujahedeen,” he said. “And I define victory as martyrdom … or victory on the ground.”

When the agent asked Kaliebe to reconsider and stay home, Kaliebe refused.

“If the cops were to come right now and would force me out of this car and arrest me, it would still be better for me to go to prison than for me to stay here and live a life, a demeaning life,” he said.

Kaliebe briefly cooperated with prosecutors after his arrest but then declined to help in their investigation of another Long Island man, Marcos Alonso Zea, who ultimately was convicted of helping the teen develop his plan to link up with militants in Yemen.

Zea is now serving 25 years. His attorney said Tuesday that Kaliebe stopped cooperating after being warned in prison that informants could face retribution from fellow inmates.

In a letter to the judge, prosecutors conceded that Kaliebe had painful childhood experiences, but they said he knew what he was doing when he allied himself with Zea, an extremist.

They said the teenager willingly chose a violent path and knew what he faced if arrested.

“Rare is the case where a defendant is so aware of the unlawfulness of his conduct as to actually quote the federal criminal code that applies to him during the commission of his offense,” prosecutors said.

(AP)