Probably PTSD
https://abcnews.go.com/amp/US/new-orleans-attack-latest-fbi-dhs-warn-copycat/story?id=117290889
Shamsud-Din Jabbar's foreign travel is a part of the ongoing investigation, law enforcement officials told ABC News.
Investigators are working to determine what he did during his travel in Egypt, why he went and who he interacted with while there, multiple sources said. Critical to the probe is whether he had been radicalized prior to the travel or if the travel marked the start of his radicalization.
"This next most important phase of the investigation is to find out how that radicalization happened and if it happened on that trip," Orleans Parish District Attorney Jason Williams
Two U.S. officials told ABC on Friday that, though it's still very early in the investigation, there is evidence at this time that Jabbar had been in contact with a direct ISIS representative.
NBC News was the first to report on the rare chemical.
A search of Jabbar's home in Houston also turned up bomb-making materials, sources confirmed to ABC News on Thursday. The items found were also referred to as "precursor chemicals" by agents in the field, sources said.