A federal judge sentenced Schofield Barracks soldier Ikaika Erik Kang to 25 years in prison today for trying to help the Islamic State group, or IS.

Senior U.S. District Judge Susan Oki Mollway also sentenced Kang, 35, to undergo 20 years of probation-like court supervision after he completes his prison term.

Kang, a 2001 Kaiser High School graduate and a sergeant first-class air traffic controller for the 25th Combat Aviation Brigade at Wheeler Army Airfield, pleaded guilty in August to four counts of attempting to provide material support or resources to a designated foreign terrorist organization. Each charge carries a maximum 20-year prison term.

Kang’s plea agreement called for the 25-year prison term. The government also promised not to charge Kang with federal espionage, terrorism, firearm and other crimes.

The FBI started investigating Kang in August 2016 after he was disciplined several times for arguing pro-IS views at work on post. During the investigation, the FBI discovered Kang had become radicalized, watching hours of videos of IS executions and telling a confidential source he was going to attack Schofield as a suicide bomber, the government said.

Kang admitted he gave undercover FBI agents he thought were IS fighters or people connected to IS sensitive military documents on U.S. military weapons capabilities, mobile airspace management, air traffic control call signs, radio frequencies and other classified information.

He also admitted to making a training video on fighting techniques for the undercover agents and giving them military gear and a commercially available camera-mounted drone for use in tracking U.S. troop movements.

On the day he was arrested in July last year, the FBI said Kang pledged his loyalty to the IS leader, kissed the IS flag and said he wanted to kill a bunch of people.

Kang “expressed a desire to commit a shooting in downtown (Honolulu) and in Waikiki later that same day,” U.S. Attorney Kenji Price said in August after Kang pleaded guilty.

Kang’s older sister told Mollway in a letter to the court that her brother grew up in a mentally and physically abusive household and that his father suffered from mental health issues. Two former Army supervisors said in their letters to the court that Kang had his own mental health issues and was susceptible to external influence.