Updated

The husband of a military servicewoman living on a Tennessee Naval base is under investigation for posting threatening comments on a radical right-wing Web site, FoxNews.com has learned.

Investigators with the Naval Criminal Investigative Service have seized the man's shotgun and taken it to the armory at the Naval Support Activity Mid-South base in Millington, Tenn. The firearm will be will be stored there while the agency's probe continues.

The man, writing under the name "ACA," posted a comment last week in response to a story on the expanding role of the IRS under the new health care law. The story was posted on infowars.com, which is operated by conservative talk-show host Alex Jones.

In response to comments made by a poster who questioned others' commitment to violence against government workers, "ACA" wrote:

"THEN I WILL ( I here by threatn you with violence) if you come to my door [address removed] see if im joking! and as for you BEN what dose it look like? you living in it right now! IVAN go buy a gun and get some practice in... ..."

His post generated a response by someone calling himself "Madman," who wrote:

"Who threatened? Threats are things said, that you don't really intend on doing, to hopefully make an advisory cower in fear. We made promises, to protect our family, and our property against armed aggressors,"before re-posting the address of the Naval base.

Both posts have been removed from the site.

Earlier this month, "ACA" posted a series of comments in which he talked about killing police officers and other law enforcers. In one, he claimed to keep an AR-15 assault rifle by his door and a loaded 12-gauge shotgun nearby, and he said he'd like to use both to kill police. The Naval base spokesman said only one weapon, the shotgun, was removed from the man's home.

"ACA" has also praised the actions of Joseph Stack, the anti-tax Texan who last month crashed a small plane into an Austin building that houses an IRS office, killing one of their workers. "ACA" said in one online post that Stack didn't have enough explosives on board the plane. In other posts, he implored others to target Transportation Security Administration employees. And in an even earlier post, he wrote, "T.S.A. ... ... ... ... .truly .stupid .assholes! the guy that lived next to me worked for them and i made his life a liveing hell till he moved!"

On Monday morning, NCIS agents and base security located "ACA" at the address — a privately owned on-base housing unit — that he posted in his recent comment on infowars.com. He admitted to posting the comment, said base spokesman David Crenshaw. The man's name was not revealed.

"Based on the statements, the installation commanding officer requested that the resident surrender any weapons to base security for safekeeping until an investigation could be completed. The resident was cooperative and complied with the request," Crenshaw said.

"The Naval Criminal Investigative Service and the Installation Security Team are conducting an investigation into the statements to determine if there was any criminal wrongdoing."

This action was taken after FoxNews.com inquired about the online comment.

Even though he is a civilian, the man is living on a military base, making him subject to the rules of that base. The commanding officer has the authority to take any weapons that are on the base — whether they belong to a member of the military or a civilian — and store them at the armory. For the same reason, NCIS has the authority to arrest him.

The man, who has not been charged, will be permitted to check his shotgun out of the armory, but he will be monitored while doing so, Crenshaw said.

NCIS and the base's security force will continue to monitor the man as they conducts their investigation. Thus far, Crenshaw said, it appeared to investigators that the man had not violated any law.

"Threatening violence is taken very seriously but it is not necessarily an illegal act — there's freedom of speech," Crenshaw said, adding that investigators would step in if they sensed the man was going to take action and that his online rants were more than just blather.

Crenshaw said he did not know if "Madman," the commenter who replied to "ACA's" post, was being sought by investigators.