The friend who allegedly supplied the Southern California jihadist couple with the guns used in last week's terror attack - and who sources said could soon be charged in connection with the case - presented himself to friends as “laid back” but seemed to be in constant personal conflict.

Enrique Marquez was married, but didn’t live with his wife. He had converted to Islam but confided in a mosque worker that he wanted to become a Buddhist. He could be witty and laugh at himself, but often posted dejected missives on Facebook.

And he was reportedly not a particularly pious Muslim and even spoke of joining the military – yet he allegedly plotted a scuttled terror attack with boyhood friend Syed Farook and is believed to have purchased two of the weapons Farook and his wife, Tashfeen Malik, would eventually use to murder 14 people and injure 21 others at a holiday party on Dec. 2. Farook and Malik were killed in a subsequent shootout, and Marquez has so far been cooperating with authorities.

“It was hard to make a conclusion about what he was like,” Sid Hashemi, a former boss of Marquez, told Reuters.

“None of them seemed like they were married. It was very weird.”

- Brittani Adams

Marquez, 24, bounced from job to job – serving as an unarmed security guard at construction sites, working security at a local bar and checking customers’ receipts at Walmart, according to Reuters.

“He just floated around,” Hashemi said.

Marquez was never able to maintain employment anywhere for too long, with his personality seeming to block any potential progress. An account manager at one of the security firms that employed Marquez told Reuters that Marquez “just couldn’t take the stress” after he received a promotion. Ashlee Sims, who worked with Marquez at a Walmart Supercenter in Corona, said he was withdrawn and “awkward.”

He has since been fired from Walmart, spokesman Brick Nick told Reuters.

One of the more unusual aspects of Marquez’s personal life was his marriage to Mariya Chernykh.

Chernykh, 25, came to the U.S. from Russia in 2009 on a visa for work or study exchange programs, according to a federal official who spoke to the Washington Times. Chernykh initially worked in the mall for her sister Tatiana, who is married to Farook’s brother, Syed Raheel Farook. It’s unclear how or when Marquez met Chernykh, but the two were married on Nov. 29, 2014. The couple’s marriage license said the ceremony occurred at the Islamic Society of Corona-Norco, though the mosque’s facility manager denied that to the Washington Times.

Raheel Farook vouched for Chernykh on her citizenship application, saying that Marquez would be able to financially support his new bride, according to ABC News.

Beyond those official documents, however, Marquez and Chernykh didn’t appear to have much of a relationship.

“It was like an arranged marriage,” Michael G. Stone, a friend of Marquez’s, told ABC News.

Brittani Adams told the Los Angeles Times she didn’t even know Marquez was married and that he and Chernykh didn’t act like a couple.

“He would never leave with her, come with her, not hug her,” she said. “None of them seemed like they were married. It was very weird.”

Marquez lived with his mom, not Chernykh.

“I saw no sign of him having a wife – it was only his mom in the house,” neighbor Lori Aguirre told Reuters.

Chernykh lived with another man, Oscar Romero, according to public records reviewed by ABC News. Social media photos reportedly show Chernykh, Romero and a baby girl identified as the pair’s daughter. Chernykh called herself Maria Romero on Russian social media sites and Oscar named Chernykh as his wife on one of his social accounts, according to ABC News.

Whether truly wed, engaged in a sham marriage or estranged, the situation struck observers as strange, and apparently weighed on Marquez.

“Whenever he would talk about it, he would look sad,” Viviana Ramirez told ABC News. “He never really talked about her or brought her around, but it just didn’t seem like it was going in a positive direction.”

The day before the San Bernardino attack, Marquez messaged Ramirez.

“He messaged me…about relationships,” she said. “How one person loves the other one more than – you know, it’s more one-sided than them together.”

Marquez lived next door to future terrorist Farook when the two were teenagers, bonding over automotive repair, despite the fact that Farook was four years older than Marquez, Reuters reported.

Farook reportedly began growing more serious about Islam in 2008, and that’s around when Marquez converted to Islam – though he never appeared to be a devout Muslim.

Marquez worshipped at the Islamic Society of Corona-Norco a few times, the Washington Times reported, and the mosque’s facility manager told Reuters that he spoke to Marquez around 2012 to communicate “that Islam was not for him.”

But there was either some radical but private beliefs in Marquez, or he was merely Farook’s willing lackey, because the pair plotted “an actual attack” in 2012, according to Sen. Jim Risch, R-Idaho, who is on the Senate Select Committee on Intelligence.

It was around this time that Marquez bought a Smith & Wesson M&P15 and a .223-caliber DPMS Model A-15, according to the LA Times. Those guns eventually made their way into Farook’s custody and were part of the arsenal used during the San Bernardino attack in 2015.

But Marquez and Farook’s initial plot never came to fruition. The men were spooked by a series of terror arrests in Riverside County in November 2012, Fox News has learned.

Shortly thereafter, the close friends drifted apart. Even as Marquez maintained a friendship with Raheel Farook, he withdrew from his boyhood friend.

A neighbor of Marquez told Reuters that she saw Marquez and Farook standing on the street one day without acknowledging each other.

She didn’t see them together again.

Tommy Lopez, a friend of Marquez, told the Washington Times he saw his buddy within the past month. Marquez fell asleep and Lopez and another man stacked beer cans on his body.

“When he woke up he just started laughing,” Lopez said. “He was a pretty laid-back guy.”