An Iranian man who came to Maine as a refugee in 2009 was fighting for the Islamic State group when he was killed last year in Lebanon, investigators said.

Details about Adnan Fazeli, 38, were revealed in newly unsealed court documents filed in federal court in Portland, the Portland Press Herald reported.

Fazeli, a Muslim who was most recently a Freeport resident, became radicalized while living in Maine, the newspaper reported. He came under FBI investigation for his connection to Islamic State shortly after leaving his job at a Portland auto dealer and flying to Turkey in August 2013. He never came back.

Fazeli died in battle in January 2015 as a member of an Islamic State force of about 150. The group was turned away by the Lebanese army.

The Press Herald reported that the details of Fazeli's case were never revealed publicly before and were contained in an affidavit that was filed in U.S. District Court in Portland in October and unsealed on Monday.

In the affidavit, written by a state police detective on an FBI task force, four FBI informants described Fazeli's changes about a year after he came to Maine through Catholic Charities Refugee and Immigration Services. The informants said Fazeli would watch Islamic videos on the internet for hours and began voicing anti-American sentiments.

Fazeli's 25-year-old nephew Ebrahim Fazeli said his uncle was an "educated, smart guy" who had become more religious, but relatives didn't realize he had become radicalized.

The family learned what Adnan Fazeli was up to when he contacted his wife from overseas, Ebrahim Fazeli said. Ebrahim Fazeli said that's when he contacted authorities, because he feared for his aunt and the couple's three children.

"I wanted to protect them from him," Ebrahim Fazeli said. "It was very clear to me that they weren't important to him."