Fox: Wife of Orlando Shooter Knew of Plans

The wife of the gunman who killed 49 people at an Orlando gay nightclub could soon be charged in connection with the attack, the deadliest mass shooting in modern U.S. history, a law enforcement source said on Tuesday. 

FoxNews.com, citing an FBI source, said prosecutors had convened a grand jury to investigate Omar Mateen's wife, Noor Salman. They are seeking to charge her as an accessory to 49 counts of murder and 53 counts of attempted murder and failure to notify law enforcement about the pending attack and lying to federal agents.

NBC News, citing multiple unnamed sources, said Salman told federal agents she tried to talk her husband out of carrying out the attack. But she also told the FBI she once drove him to the nightclub, Pulse, because he wanted to scope it out, the network said.

Mateen, who was shot to death by police after a three-hour standoff at the club early on Sunday, called 911 during his rampage to profess allegiance to various militant Islamist groups.

Federal investigators have said he was likely self-radicalized and there was no evidence that he received any instruction or aid from outside groups such as Islamic State. Mateen, 29, was a U.S. citizen, born in New York of Afghan immigrant parents.

"He appears to have been an angry, disturbed, unstable young man who became radicalized," President Barack Obama told reporters after a meeting of the White House National Security Council.

One official familiar with the investigation, who spoke on condition of anonymity, said investigators were only beginning to delve into the contents of Mateen's cellphone and other electronic devices.

The source said investigators believe Mateen browsed militant Islamist material on the internet for two years or more before the Orlando shootings.