The former neighbor who supplied the assault-style weapons to the San Bernardino killers is related to them by marriage and recently told a friend that there were Muslims nearby “ready to go haywire,” according to reports.

Enrique Marquez was married last year to Mariya Chernykh, whose sister is the wife of Raheel Farook, brother of mass murderer Syed Rizwan Farook, Reuters reported, citing marriage documents.

Michael G. Stone, a friend of Marquez from the local punk scene, told ABC News that his friend had told him something a few months ago that he now sees in a new light.

“He said something along the lines of, ‘There’s a lot of Muslims in our own back yard, just ready to go haywire and attack,’” Stone said. “And we didn’t think nothing of it. We just brushed it aside, you know. He was drunk, so I don’t know.”

The Farook brothers lived next door to Marquez when they were growing up, though the brothers had both since moved, Reuters reported.

The marriage documents show that Marquez married Chernykh on Nov. 29, 2014. It could not be determined whether they live together.

Witnesses to the marriage were Mariya’s sister, Tatiana Farook, and Tatiana’s husband, Raheel Farook, Reuters reported.

Raheel Farook married Tatiana, then known as Tatiana Gigliotti, on Sept. 10, 2011, the documents show.

Marquez, described by several neighbors as a good friend of Farook, bought the two .223-caliber rifles legally, according to the US Bureau of Alcohol, Tobacco, Firearms and Explosives.

Employees at a Walmart in Corona, Calif., 20 minutes by car from Riverside, said Marquez has been working there as an asset protection and customer specialist for about six months. He was last seen there on Nov. 29, they said.

Marquez, who had checked himself into a psychiatric facility after the shooting, was questioned by the feds after they raided his home in Riverside on Saturday. He has not been charged.