Joshua Jahn, the 29-year-old who killed two detainees and wounded another at a Dallas ICE facility in September before taking his own life, was described by his parents as “completely normal” before returning to Texas from Washington state.

Records reveal he believed he suffered from “radiation sickness” and was “allergic to plastic,” wore gloves to avoid contact with plastic, and practiced target shooting with a newly purchased rifle in Oklahoma shortly before the attack.

Jahn, who had no diagnosed mental or physical conditions, was socially isolated, unemployed, and spent much of his time playing computer games.

The attack victims were Norlan Guzman-Fuentes, 37, and Miguel Angel Garcia-Hernandez, 32, who died, and Jose Andres Bordones-Molina, who was wounded but released, CBS News has reported.

Investigators found no clear motive, though Jahn left notes and inscribed “ANTI-ICE” on a bullet, indicating a desire to ambush and terrorize ICE agents.