The Marine Corps is investigating a deployed machine-gunner with possible neo-Nazi sympathies who told a Jewish journalist earlier this week on Instagram that her religion is “that of satan.”

Talia Lavin, who published a book last week on how white supremacists organize online, said that Marine Lance Cpl. Joseph Mercurio “randomly commented” on her Instagram profile with the antisemitic remark. Then she clicked over to his account and found in his bio below “USMC 0331” a quote from a prominent white nationalist leader and lyrics from a Neo-Nazi punk rock band.

Marine Corps photo

Additionally, Mercurio’s username included “88,” which is commonly used in neo-Nazi circles as shorthand for “HH,” or “Heil Hitler.” Mercurio, 20, an infantryman with 2nd Battalion, 4th Marine Regiment, removed the numbers from his username and the quotes soon after Lavin posted the screenshots.

By Wednesday, Mercurio’s bio said only “USMC 0331.” But a review of Mercurio’s Facebook profile by Task & Purpose found an antisemitic cartoon traced back to The Daily Stormer, a neo-Nazi website, and a post that was written days after the death of George Floyd in the custody of Minneapolis police in which he suggested protesters were acting “like wild animals.”

“Trump was once a great development and had tons of potential but flushed it all away,” Mercurio wrote alongside the cartoon on Facebook in June, which showed Trump holding a burning paper with “America First” in one hand while holding the flag of Israel in the other. “2016 he had me and millions of others energized but he let all of us down. What a fucking joke.”

Marine Corps photo

A native of Pennsylvania, Mercurio graduated from Marine recruit training in Sept. 2019. He has been with 2/4 since Nov. 2019.

Mercurio did not respond to messages from Task & Purpose.

“I can confirm that the command is investigating,” said Capt. Joe Butterfield, a Marine spokesman. “Further information is limited because the investigation is ongoing.”

“We are serious about holding ourselves accountable,” Butterfield said. “We have spoken clearly on the Marine Corps’ position on racial hatred, extremism, and behavior incongruent with our core values: it will be investigated immediately, and if substantiated, the individual(s) will be held appropriately accountable.”

The outing of a suspected Nazi sympathizer in the ranks comes weeks after another Twitter user posted a video on Oct. 8 of Marine Pfc. Jarrett Morford, 20, in which he threatened to kill Chinese people after he finished training and got to his unit. More than two dozen Marines have been investigated over extremist or racist ties since 2017, including at least one officer.

Related: Meet the (probably soon to be former) Marine who just dropped a not-so-hot racist track on Instagram

The number of hate groups in the United States has increased dramatically since 2000, while a 2008 FBI report warned that various far-right extremist leaders were “making a concerted effort to recruit active-duty soldiers and recent combat veterans of the wars in Iraq and Afghanistan,” adding that “those with military experience often hold positions of authority within the groups to which they belong.”

“White supremacists encourage joining law enforcement or the military,” Levin told Task & Purpose. “To gain access to guns and potential recruits.”

More recently, a 2019 Military Times survey found that 36% of respondents had seen evidence of white supremacist and racist ideologies in the military, up from 22% in 2018.

“People subscribing to some kind of white supremacist-type ideology is certainly the biggest chunk of” potential domestic terrorism threats, FBI Director Christopher Wray told lawmakers in September. 

“Divisiveness leads to defeat,” said Gen. Mark Milley, chairman of the Joint Chiefs of Staff, in testimony to Congress in July. “As one of our famous presidents said, ‘a house divided does not stand.’ Our troops, a part of cohesive teams consisting of people of different races and genders and religions, and sexual orientations, are working to accomplish their mission in peace and war all over the globe. Equality and opportunity are matters of military readiness. Not just political correctness. There is no place in our armed forces for manifestations or symbols of racism, bias, or discrimination.”