A 22-year-old man is dead after opening fire on the Earle Cabell Federal Building on Monday and the investigation into him and what caused him to shoot at and outside the building is underway.
Investigators are working to retrace Brian Isaack Clyde's whereabouts in the days and hours before the shooting.
Clyde attended Woodrow Wilson High School in Dallas for part of his freshman year in 2012. According to DISD, he withdrew and moved to Austin later that year.
Public records indicate Clyde also lived in Corpus Christi where he just graduated from Del Mar College in the spring with an associate's degree. He has family locally and out of state.
Clyde's social media pages show photos and references to service in the military. The FBI said Clyde was discharged from the Army in 2017 but didn't elaborate any further.
There were no previous run-ins with authorities, according to a records check by FOX4. Federal agents said he was not any watch list of any kind prior to Monday's shooting.
Clyde was listed as a Spring 2019 graduate of Del Mar College in Corpus Christi on the school's website. He earned an associate's degree in applied science, according to the school.
Much of what is known about Clyde comes from his Facebook page, which did not have privacy restrictions turned on and featured numerous posts viewable to the public.
In posts over the weekend, Clyde uploaded photos of what appeared to be some type of fixed-blade weapon and numerous ammunition magazines.
"I decided to finish getting all of my mags. 2 40 rounders and 8 30 rounders total," Clyde wrote with the photo of the magazines.
Last weekend he posted a video, in which he says at one point, "I don't know how much longer I have, but the [expletive] storm is coming."
Clyde's Facebook page stated he attended Woodrow Wilson High School in Dallas and Leander High School.
Clyde also said he enlisted in the Army. Photos show him in fatigues, and he said he was stationed at Fort Campbell in Kentucky. Other than his 2017 discharge, nothing is publicly known about his time in the service. FBI officials said they were working with the Department of Defense to learn more about his service record.
The suspect's father currently lives in Arizona. Rodney Clyde answered the phone when FOX4 called on Monday afternoon but said he didn't know what was going on and didn't comment any further.
ATF officials are working to trace Clyde's firearm. A possible motive has not been released.