A Hawaii-based American soldier will plead guilty to charges of trying to join the Islamic State (ISIS), his lawyer told the Associated Press on Wednesday.

Sgt. 1st Class Ikaika Kang will enter the plea following court documents showing Kang provided classified military material to undercover agents he believed were working for ISIS.

“We’ve agreed on a sentence,” said the assistant federal defender, Alexander Silvert, which will see him imprisoned for 25 years rather than for life. He referred all further questions to Kang’s attorney, Birney Bervar. He is now expected to enter his guilty plea when he appears in court on Thursday.

According to a court affidavit unsealed on Wednesday, Kang started researching Islam in 2014 and quickly became eager to travel to the Middle East to “join the cause” and was “only in the military for a paycheck.”

Kang told an FBI informant that he planned to carry out a suicide bombing on the Schofield Barracks in Hawaii and pledged allegiance to the caliphate during a meeting with undercover agents in Honolulu, where he kissed the ISIS flag.

He was also reportedly in the habit of watching graphic videos, such as beheadings and other brutal violence, for hours every day and had a history of making threatening statements, ABC reported. One informant claimed he spoke of a desire to “take his rifle, his magazines, and ‘kill a bunch of people’” and researched on YouTube “the most effective and painful ways people had been tortured.”

Having previously viewed the Islamic State as a group of “bloodthirsty” murderers, he came to believe that jihadist groups were oppressed and sought to help them in any way possible.

Bervar claims Kang may suffer from post-service mental health issues that authorities were aware of but failed to treat.

Having grown up in Hawaii, Kang joined the Army in December 2001, months after the 9/11 terror attacks. He served tours in South Korea between 2002 and 2003, Iraq from March 2010 to February 2011, and Afghanistan from July 2013 to April 2014.

The 35-year-old, who has been detained without bail since his arrest last year, is the first active-duty service member to be charged with material support for ISIS and has, consequently, had his duty status changed to “confined.” He will return to court on Thursday.

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