UPDATE 14-Wife of Orlando shooter knew of attack, could soon be charged -source
* Gunman's wife could be charged as soon as Wednesday
* Obama calls U.S.-born killer "angry, disturbed, unstable"
* Shooter apparently self-radicalized, largely by internet (Adds comment from shooter's first wife)
By Letitia Stein and Julia Edwards
ORLANDO, Fla./WASHINGTON, June 14 (Reuters) - The wife of the gunman who killed 49 people at an Orlando gay nightclub knew of his plans for the attack and could soon be charged in connection with the deadliest mass shooting in modern U.S. history, a law enforcement source said on Tuesday.
The source told Reuters that a federal grand jury had been convened and could charge Omar Mateen's wife, Noor Salman, as early as Wednesday.
"It appears she had some knowledge of what was going on," said U.S. Senator Angus King, a member of the Senate Intelligence Committee, which received a briefing on the attack on Tuesday.
"She definitely is, I guess you would say, a person of interest right now and appears to be cooperating and can provide us with some important information," King told CNN.
Mateen, who was shot dead by police after a three-hour standoff at the Pulse club early on Sunday, called 911 during his shooting spree to profess allegiance to various militant Islamist groups. Continuación...