(CNN) The wife of Orlando nightclub shooter told the FBI that Omar Mir Seddique Mateen said he wanted to carry out a jihadist attack, though she denied knowledge of his plans to launch the deadliest mass shooting in U.S. history, a law enforcement official told CNN on Tuesday.

FBI investigators don't believe Noor Salman was a co-conspirator in the attack that killed 49 people Sunday morning at Pulse, the source said.

Omar Mir Seddique Mateen poses with his wife, Noor Salman, in a family photo posted online.

But authorities are looking into whether she should face charges for what she may have known of his intentions and possibly failed to report to law enforcement.

The development comes as investigators try to understand what motivated Mateen to carry out the devastating attack . Forty-nine people were killed early Sunday and 53 people were wounded. Officials said that 28 victims are still hospitalized, including at least four people who are in critical condition.

Salman, Mateen's second wife, has been cooperating with various law enforcement agencies. The couple has been married since 2011. They have a 3-year-old son.