An 18-year-old recently arrested on terrorism charges in Arizona has the mental capacity of a child and had been in regular contact with the FBI for years before his arrest, according to family members, former teachers, and medical documents reviewed by The Intercept. Mahin Khan was arrested July 1 on charges of plotting to support the Taliban as well as the militant group the Islamic State and commit acts of terrorism in the local community.

People close to Khan say he had serious mental health and developmental issues and the FBI was aware of this, having met with him regularly since he was a young teenager. According to medical records and statements from family members, he was first referred to the FBI after sending a threatening email to one of his teachers at the age of 15. After an initial meeting with the FBI, he spent 45 days at an inpatient psychiatric facility for evaluation. His family says this stay at the facility was coordinated with FBI officials. Agents reportedly continued to meet with Khan regularly after he returned home and continued to do so up until the time of his arrest.

A community activist told The Intercept that after Khan’s initial contact with the FBI, he began regularly meeting with the teenager in an attempt to mentor him. He said that during these meetings, Khan had exhibited obvious signs of mental illness. “He was unable to even tie his shoelaces and his mother would have to do it for him. He would say things supporting extremism and terrorist groups but then would later start crying and apologizing,” the activist said. The activist did not want to be named for fear of retribution from law enforcement.

His statement echoed those made by a former tutor of Khan’s in an interview with local Arizona media, in which the tutor said Khan had “the mentality of a 6-year-old” and he had told Khan’s mother that there was no point in having him tutored as he was “unable to learn anything.”

In a statement released to local media shortly after Khan’s arrest, his family said he was developmentally delayed and suggested that he had autism. The statement also mentioned that “three years ago, Mahin went through an extensive inpatient psychiatric evaluation under the directive and supervision of the FBI. The evaluation documented the extent and severity of his mental health.”

Medical documents reviewed by The Intercept seem to confirm that Khan had cognitive impairments. A developmental evaluation conducted by psychologists last year found that Khan “requires considerable support from parents to complete day-to-day skills.” It also said that he had been adversely impacted by the loss of his older brother, who died after suffering cardiac arrest a year earlier.

Another document released by his former therapist’s office stated that doctors observed Khan, “acts younger than his stated age,” adding that his “concept formation and mental processing also lack maturity and forethought.”

Further medical records showed that Khan had been taking anti-psychotic medication in recent years.