A suburban New York man who was thwarted in his attempt to fly to Yemen to join a Middle Eastern terrorist group and then admitted continuing to plot with others to assist them was sentenced Monday to 25 years in prison.

Marcos Alonso Zea, 26, of Brentwood, pleaded guilty in September to attempting to provide material support to al-Qaida in the Arabian Peninsula, also known as Ansar al-Sharia, and obstruction of justice.

Federal prosecutors said the Brentwood, Long Island, man flew to London on his way to Yemen in January 2012. He was rejected by customs officials in London and returned to the United States. Once home, prosecutors say, Zea continued participating in the conspiracy. He was arrested in October 2013.

U.S. District Court Judge Sandra Feuerstein rejected an appeal for lenience from Zea’s attorney, Marc Bogatin, who argued that despite the guilty plea, his client had not actually committed any violent acts that would require him to receive the maximum penalty. Had he gone to trial, Zea could have faced up to life in prison. Bogatin suggested that Zea be sentenced to about 10 years in prison.

Feuerstein appeared dubious at that contention, noting that Zea admitted wanting to assist the terror group.

“Why, if not to support them?” she asked. “Then why was he going there?”

Bogatin countered that there “was no evidence that he intended to fight.”

Zea declined to comment when given an opportunity by the judge to make a statement.

Later, the judge told him his sentence should serve as deterrent. “I think there has to be a message to others that this is conduct that is absolutely unacceptable,” she said.

U.S. Attorney Loretta Lynch said in a statement that Zea “presents a chilling reminder of the danger presented to the United States by homegrown terrorists. Born, raised, and schooled in the United States, the defendant nevertheless betrayed his country by attempting to join al-Qaeda in the Arabian Peninsula, assisting a co-conspirator’s attempt to join that terrorist group, and, after learning he was under investigation, attempting to destroy evidence of his guilt.”

Prosecutors said Zea, who converted to Islam several years before his arrest, gave money to and instructed co-conspirator Justin Kaliebe, also of Long Island, on how to evade electronic surveillance by law enforcement as he discussed Kaliebe’s plans to wage jihad.

Zea, who worked as a clerk at a home improvement store, was inspired by terrorist propaganda, according to the FBI.

Among Islamic extremist materials found on Zea’s computer were issues of an al-Qaida publication that promotes violent jihad, authorities said. The publication contained articles such as “Which is Better: Martyrdom or Victory?” ”Why did I choose al Qaida?” and “What to Expect in Jihad?”

Investigators said they also found a video produced by al-Qaida depicting detonation of an explosive device on a vehicle carrying Western military personnel.

Zea also admitted giving money to and instructing co-conspirator Justin Kaliebe, also of Brentwood, on how to elude law enforcement surveillance.

Kaliebe, 20, pleaded guilty in a secret federal court proceeding in 2013 to attempting to provide material support to a terrorist organization. He faces a sentencing hearing next month. His attorney has said Kaliebe was diagnosed with a form of autism as a child and did not understand the gravity of what he was doing.

Both men appear to have been swept up in the New York Police Department’s ongoing investigation into the activities of Muslims throughout the region.

About nine relatives and friends of Zea’s sat stoically in the courtroom during the sentencing and declined to speak with reporters after the proceeding.

(AP)