Newly disclosed documents reveal insights into the background of the 29-year-old shooter who unleashed gunfire at a Dallas immigration center last month. According to police records, the shooter’s parents described him as “completely normal” until a move to Washington state, after which he returned home claiming to suffer from radiation sickness.

The gunman, identified as Joshua Jahn, had taken up wearing cotton gloves to avoid touching plastic and had recently engaged in target practice with a new rifle in Oklahoma. This practice occurred just a month before his deadly assault on the U.S. Immigration and Customs Enforcement facility, where he launched his attack from a rooftop, as detailed in a report by an officer from the Fairview Police Department.

In the tragic events of September 24, Jahn fatally shot two detainees and injured another before ending his own life.

Despite the breadth of information in the records, obtained by The Associated Press under an open records request, the motive behind Jahn’s actions remains unclear. Federal investigators had previously noted that Jahn inscribed “ANTI-ICE” on a bullet and left behind handwritten notes expressing his intention to ambush and instill fear in ICE agents.