San Bernardino gunman plotted attack with neighbor

Enrique Marquez Jr. who purchased the two military-style rifles several years ago that Syed Rizwan Farook and Tashfeen Malik used in the attack that killed 14 people at the Inland Regional Center, has emerged as a key figure in the  investigation.

• He purchased the weapons in 2011 or 2012, around the time Farook is believed to have begun considering carrying out a terrorist attack in the U.S.
• Marquez also converted to Islam around that time.
• Marquez lived next door to Farook on Tomlinson Avenue in Riverside for many years. He also cemented his connection to his next-door neighbor by marrying the sister of Farook's sister-in-law last year.
• The circumstances of the marriage are now also under investigation.
• Hours after the deadly attacks in San Bernardino, a cryptic message was posted on Marquez's Facebook page.  “I’m. Very sorry sguys (sic)," it read. "It was a pleasure.”
• Marquez checked himself into a mental health facility following the attacks.