Salman has told the FBI that she accompanied her husband to Pulse at least once prior to the massacre, in a trip that a US law enforcement official described as "reconnaissance".
"With respect to the wife, I can tell you that that is only one of many interviews we have done and will continue to do," Ronald Hopper, FBI assistant special agent in charge, said at a news conference.
Salman grew up in Rodeo, California, a community about 40km northeast of San Francisco, in a family with Palestinian roots, AP reported.
Neighbours of her family in California told the Washington Post that she did not live in the home and had married Mateen a few years earlier. Salman was described as friendly, outgoing and stylish.
Her father died in 2015, and that was the last time the neighbours saw her.
"You know, some kids after high school, they open up the box and the world is theirs. She was inside the box, just pack it up and get married," a neighbour, Jasbinder Chahal, told AP.
Chahal said that Salman and Mateen had a small wedding and "took lots of pictures here at the house". She described a sheltered childhood for Salman and her sisters, saying, "Noor never played in the street, and the girls were never allowed to drive."
Other neighbours who spoke to the Post, however, recalled her playing softball and described her family as modern Muslims.
Both Salman and Mateen had previously been married. Mateen's ex-wife has described him as abusive and unstable.
