The suspect deliberately rammed the pickup truck into the Fox 4 studio in downtown Dallas, witnesses said.
Police were called to the 400 block of N. Griffin Street on Wednesday at approximately 12.12pm BST (6.12am local time).
According to witnesses, the man crashed into the window of one of the offices a first time.
He then backed out and returned, driving through the building a second time.
Once he got out of the car, he left papers and a "suspicious bag" behind, witnesses added, prompting the intervention of a bomb squad.
The man was also heard "ranting about treason" to employees.
Fox 4 took to Twitter to report the events unfoldind, writing: “A man crashed a truck into the side of our building this morning.
"He jumped out and started ranting.
“He’s in custody now but the bomb squad is on its way.
“He left behind a suspicious bag."
Officers from the bomb squad used remote controlled bomb robot and K-9 were seen analysing the bag.
They left at approximately 3pm, with Hanna Battah, news reporter and anchor at Fox 4, saying she saw "officers shaking hands near crime scene so it appears to be a positive sign."
Dramatic images show papers scattered on the ground and the rubbles left by the crash.