For a rarity, Fox News has useful information on what Raub was posting:

A former Marine involuntarily detained for psychiatric evaluation for posting strident anti-government messages on Facebook has received an outpouring of support from people who say authorities are trampling on his First Amendment rights.

Brandon J. Raub, 26, has been in custody since FBI, Secret Service agents and police in Virginia’s Chesterfield County questioned him Thursday evening about what they said were ominous posts talking about a coming revolution. In one message earlier this month according to authorities, Raub wrote: “Sharpen my axe; I’m here to sever heads.”

SNIP

Thomas said her son, who served tours as a combat engineer in Iraq and Afghanistan, is “concerned about all the wars we’ve experienced” and believes the U.S. government was complicit in the Sept. 11 terrorist attacks. One of his Facebook posts, she said, pictured the gaping hole in the Pentagon and asked “where’s the plane?”

( allbolding mine)

So what we have here is a veteran who was putting out violent messages and whose mind was in flight from reality (belief in “9/11 Truth” is fleeing from reality). In the wake of the Virginia Tech, Tuscon, and Aurora mass shootings, I must defend the Virginia state police for taking Raub into custody. He his words and thoughts may well have been signs of someone breaking with reality and about to turn violent. Law enforcement was right to protect both the public and Raub by detaining him for evaluation and treatment.