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Gun rights advocates have a California police detective in their crosshairs after he apparently posted comments on Facebook advocating that "open carry" supporters should be shot.

East Palo Alto Police Det. Rod Tuason apparently posted the remarks on his Facebook page in response to a friend's status update, which suggested that gun advocates who carry unloaded weapons openly — which is legal in California — should do so in places like "Oakland, Richmond and East Palo Alto" and not just in "hoity toity" cities.

"Haha we had one guy last week try to do it!" Tuason replied. "He got proned out [laid face-down on the ground] and reminded where he was at and that turds will jack him for his gun in a heartbeat!"

Several comments later, the detective suggested shooting the gun rights advocates, some of whom have carried firearms openly in recent weeks in California's Bay Area, particularly at Starbucks locations.

"Sounds like you had someone practicing their 2nd amendment rights last night!" Tuason wrote. "Should've pulled the AR out and prone them all out! And if one of them makes a furtive movement … 2 weeks off!!!" -- referring to the modified duty, commonly known as desk duty, that typically follows any instance in which an officer is investigated for firing his weapon.

Those comments caught the attention of a California attorney and blogger, as well as a Virginia man who started a Facebook group calling for Tuason's termination.

John Taylor, whose Facebook group had 54 members as of midday Friday, said the Facebook thread confirmed gun owners' worst fears.

"Any sworn officer who suggests shooting law-abiding citizens for exercising their most basic constitutional rights deserves the full wrath of America's gun owners," Taylor told FoxNews.com. "It's an affront."

California's Penal Code makes it illegal to carry concealed weapons without a county-issued license. But it is legal to carry an unloaded weapon in plain view in a holster. In most cases, it is illegal for an unconcealed weapon to be loaded.

Taylor, of Arlington, Va., who has a concealed weapons permit in his home state, said he planned to write a letter to the East Palo Alto Police Department demanding that Tuason be fired.

"The targeting, harassment and intimidation of law-abiding citizens who are peacefully agitating for their rights by a police officer is an abomination to the Constitution, and is in fact the exact reason our Founding Fathers created the Second Amendment," Taylor said. "Police officers who think they are going to get between law-abiding Americans and their Second Amendment rights are going to find themselves in the line of fire."

Tuason's comments were first noticed by California attorney Kevin Thomason, who posted a screen grab of the detective's remarks on his Web site on Sunday.

"[Tuason] didn't realize that actual PRO-GUN people also read Facebook," Thomason wrote. "Amazingly, he posted the following comment about law abiding gun owners on a friend's page. Basically, he's saying 'prone them out' (face down on the ground), and if anyone moves, kill them. I don't make this crap up."

Thomason, a member of the National Rifle Association, wrote that Tuason's comments were "worth a call" to the East Palo Alto City Council, as well as to his superior officers.

Tuason, who has since removed his Facebook profile, did not return messages seeking comment on Friday. He is reportedly being investigated by the police department's professional standards division regarding the Facebook remarks.

East Palo Alto Police Sgt. Rod Norris said he was unable to comment on the matter, but Capt. Carl Estelle told the San Jose Mercury News that police officials must be careful not to violate Tuason's First Amendment rights, since the comments appeared on his personal Web site.

"In no way are his personal comments reflective of any policies or procedures here at the department nor does he speak for the police department," Estelle told the newspaper.