Enrique Marquez, Syed Farook's former neighbor, likely to be charged

SAN BERNARDINO, CA (KTRK) -- Enrique Marquez, the former neighbor of San Bernardino shooter Syed Farook, is likely to be charged as early as Thursday in connection with the investigation, sources tell ABC News.

Marquez, 24, purchased two of the assault-style rifles used by Farook and his wife, Tashfeen Malik, in the Dec. 2 attack, FBI officials said.

Marquez told FBI investigators that he and Farook plotted a terror attack in 2012, but shelved the plans after four people were arrested and charged in a plot to commit jihad against U.S. military bases overseas, according to ABC News.

ABC News and The Associated Press contributed to this report.