A federal grand jury is considering whether Omar Mateen's wife should face criminal charges related to the deadly attack at the Pulse nightclub in Orlando, Fla., two sources familiar with the investigation tell NPR.

On Sunday, 49 people died when Mateen opened fire and took hostages at the gay club. It was the deadliest mass shooting in modern American history, and ended when Mateen died in a shootout with police.

Now, the sources tell NPR's Dina Temple-Raston that a grand jury is looking into what Mateen's wife, Noor Salman, might have known about his plans to target Pulse and whether she should face charges in connection to the attack.

"The grand jury has been meeting for several days and could make their decision as early as today," Dina reports.

Little information was available about Salman in the hours and days following the attack — including whether or not she and Mateen were legally married. But more information is emerging about the couple, who were married in 2011 in California's Contra Costa County.

The Associated Press reports that both had previously been married to other people, and that they had a 3-year-old son together.

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