Federal authorities in Orlando and around the nation are scrambling to connect dots in the wake of Sunday's massacre by an Islamist terrorist, with potential charges looming for the gunman's wife as early as Wednesday and agents tracing possible ties to radical Muslims in the U.S. and abroad.

The all-hands-on-deck probe is aimed at determining whether Omar Mateen acted alone when he gunned down 49 patrons in a gay nightclub or others knew of his deadly plans and possibly aided him. A federal law enforcement source told FoxNews.com Tuesday that prosecutors have convened a grand jury to investigate Mateen's wife, Noor Salman, who could be charged as an accessory.

FBI agents have interviewed Omar Mateen's wife, Noor Salman, in the days since Sunday's massacre that also wounded 53 more. She is reportedly cooperating, but formal charges could help ensure she told the feds all she knows.

Multiple reports said the Rodeo, Calif., home where Salman grew up was visited by the FBI Tuesday. The FBI has refused comment to the press outside of official media briefings.

A federal law enforcement source additionally told Fox News that Salman knew of her husband's deadly plans and did nothing to stop him.

Mateen died in a shootout with police early Sunday morning. While Salman has been widely referred to as Mateen's wife, the only proof of their marriage is her listing as his wife on a 2013 mortgage document and family members who said the two were married and had a 3-year-old son.

On a separate front, the FBI is piecing together Mateen’s radical Islam roots, and two trips to Saudi Arabia could be a sign of his growing religious devotion. His stated reason for both the 2011 and 2012 trips was umrah, a Muslim pilgrimage to the Kingdom that is not as significant as the hajj, a trip all Muslims must make to Mecca at least once in their lives. Either or both of the trips could also have included a deadly diversion for terror training, according to experts who are dubious that a working-class Muslim-American would make the pilgrimage twice in two years.

The FBI took a computer, camera and other equipment from Mateen's two-bedroom condominium in Fort Pierce, some 120 miles from the scene of the shooting and hours-long hostage situation that culminated in his death.

Although ISIS has taken credit for the attack and lavished praise on Mateen, it is still unclear whether he received direction, or simply inspiration, from the terrorist group. However, Fox News reported Tuesday that Mateen was more than just an acquaintance of another radicalized terrorist who left Florida for Syria where he blew himself up in 2014.

Fox News was told the relationship between Mateen and American suicide bomber Moner Abu-Salha -- who drove 16 tons of explosives into a Syrian government facility on behalf of Al Qaeda-linked Nusra Front, was "complex." The two frequented the same Fort Pierce mosque.

Authorities are also probing Mateen's ties to Dwayne Robertson, a onetime New York gang leader who resurfaced in Orlando as an imam and is suspected by federal authorities of radicalizing Americans and sending them abroad to kill. Robertson, who was released from prison last year, denies inciting violent jihad.  

Finally, more information from relatives and people who knew Mateen in prior years continued to bring into focus a portrait of an angry and volatile bigot with conflicted feelings toward gays. His massacre is being treated as both an act of terror and a hate crime directed at the LGBT community, yet hist first wife reportedly believes Mateen himself was a closeted gay man.

Patrons at Pulse, the nightclub where he killed dozens, say he had been seen there many times and one reportedly said Mateen had contacted him using a dating app popular with the gay community.