A Virginia man who wanted to join ISIS and researched how to make bombs and weapons on the Internet was arrested Saturday while the FBI raided his home, NBC Washington reports.

Sean Andrew Duncan, who fled out of the back door barefoot with “something clenched in his fist” when FBI agents knocked on his door, was arrested for “knowingly altering, destroying, mutilating and concealing tangible objects … with the intent to impede and obstruct” an FBI investigation.

According to court documents obtained by NBC Washington, a relative first warned the FBI about Duncan in February 2016. The person said Duncan “had converted to Islam, may have been radicalized, and voiced his approval of westerners being beheaded in the Middle East.”

He and his wife were interviewed by the FBI after traveling to Turkey that same month, and Duncan deleted his Facebook account two days later. He allegedly had contact with a foreign detained ISIS supporter who told the FBI Duncan expressed interest in joining ISIS and carrying out an attack in the United States.

Duncan researched ISIS-related material, ISIS attacks, weapons, body armor and surveillance and defense tactics when he lived in Pennsylvania. He moved to Virginia in June of this year.