Christian Natal, left, and Cristian Michaels embrace in front of a memorial for the Orlando shooting victims on the front lawn of the Dr. Phillips Center for the Performing Arts. (Amanda Voisard/For the Washington Post)

The 30-year-old wife of the gunman who opened fire inside an Orlando nightclub is facing intense scrutiny as the FBI tries to determine whether she had advance knowledge of the massacre, according to federal authorities.

In interviews with Noor Z. Salman, the FBI has learned that she accompanied her husband, Omar Mateen, on at least one trip to the club before the attack for what a U.S. law enforcement official described as “reconnaissance.”

The FBI has not arrested Salman, as agents gather as much evidence as possible to determine whether she provided her husband with assistance as he prepared for the assault at the club or had any inkling of his plan.

The focus on Mateen’s wife came as investigators continued to seek a concrete motive in the attack that left 49 people dead. Mateen, 29, said he carried out the attack because he wanted “Americans to stop bombing his country,” according to a witness who survived the rampage and heard the shooter make a 911 call.

[The gun the Orlando shooter used was not an AR-15. That doesn’t change much.]

The FBI investigated Omar Mateen twice before he killed 49 people at the Pulse nightclub in Orlando. (Jason Aldag/The Washington Post)

Mateen made at least one other phone call during the standoff, to an acquaintance in Florida, two U.S. law enforcement officials said. It’s unknown what Mateen told this person.

A second U.S. law enforcement official said that investigators recovered Mateen’s phone, which they were able to access. The official said it was not an iPhone.

President Obama said Tuesday that the gunman “was an angry, disturbed, unstable young man who became radicalized.”

Obama, speaking after a meeting with his National Security Council, also said that the investigation has not turned up any suggestions that the gunman was directed by a foreign terrorist organization.

“It is increasingly clear, however, that the killer took in extremist information and propaganda over the Internet,” said Obama, who plans to travel Thursday to Orlando. Obama said that the Islamic State, a militant group also known as ISIS or ISIL, has made its propaganda “pervasive and easily accessible” and that it appeared the shooter in Orlando “absorbed some of that.”

Vice President Biden, speaking at an event in New York, suggested Tuesday that the investigation had shown that the incident was “more straightforward” than it initially appeared.

“We are getting to the bottom of this, and it’s becoming clearer and more straightforward than a lot of us even thought,” said Biden, who attended a national security meeting before the event. He did not elaborate.

1 of 25 Full Screen Autoplay Close Skip Ad × What the investigation into the Orlando mass shooting looks like View Photos Officials are scouring the site and others in the area for information about the June 12 massacre. Caption Officials are scouring the site and others in the area for information about the June 12 massacre. June 15, 2016 Law enforcement officials gather outside Pulse nightclub in Orlando during the shooting investigation. David Goldman/AP Buy Photo Wait 1 second to continue.

The bloody siege left 49 people killed and more than 50 others injured. Mateen died in a shootout with police after law enforcement decided to end the standoff three hours into the attack.

The FBI has said it was also exploring whether anti-gay bigotry prompted the attack on the popular gay nightclub. Adding another dimension to the probe, at least two witnesses at Pulse said Mateen had previously visited the club. They also said they had seen him on Jack’d, a dating app for gay men.

The bureau was also facing questions over whether it missed warning signs during a 10-month probe of the shooter that ended two years before the massacre.

During that investigation, the gunman had been placed on a terrorism watch list. His wife, Salman, had apparently never come to the attention of the FBI.

The first U.S law enforcement official said the wife warned Mateen not to carry out the attack, apparently as he was leaving Saturday night for Orlando. The official said the couple surveilled the club between June 5 and June 9. FBI officials said Mateen bought the guns in early June.

It is not clear whether Salman has an attorney. Her family, who live near San Francisco, declined to comment Tuesday.

The FBI investigated Mateen beginning in 2013, putting him under surveillance, recording his calls and using confidential informants to gauge whether he had been radicalized after the suspect talked at work about his connections with al-Qaeda and dying as a martyr.

It was during this probe, which ended in 2014, that Mateen was placed on a terrorism watch list. After the FBI closed its preliminary investigation into Mateen in 2014, his name emerged months later in a separate probe, this one looking into a Florida man who became the first American suicide bomber in Syria. Investigators said they did not find any significant ties between the two men, who attended the same mosque in Fort Pierce, Fla.

The night of the shooting, Patience Carter, 20, said she heard the gunman explain his motives during a 911 call in which he also pledged allegiance to the leader of the Islamic State.

At one point, while Carter was in the club bathroom with several other hostages, she said the gunman asked if there were any black people in the room. When one man said yes, the shooter said, “You know I don’t have a problem with black people,” Carter recalled during a news conference. “This is about my country,” Mateen said. “You guys suffered enough.”

[‘How did I walk away alive?’ The Orlando shooting through a survivor’s eyes.]

These comments further add to the uncertainty regarding what may have inspired the gunman, who was born in the United States to parents from Afghanistan. At various points, Mateen also invoked opposing militant groups such as al-Qaeda and Hezbollah.

In his comments during the 911 call from the club, Mateen also referenced the Boston Marathon bombers, according to officials. Mateen’s claim that he carried out the shooting to “stop bombing” echoed a message Boston Marathon bomber Dzhokhar Tsarnaev scrawled in a note before he was taken into custody by police. Tsarnaev, who was sentenced to death last year, wrote that the U.S. government was “killing our innocent civilians” and that as a Muslim, “I can’t stand to see such evil go unpunished.”

Florida Gov. Rick Scott (R), speaking near the scene of the slayings, said Tuesday that investigators were working diligently to sort out what happened in Orlando and why. He said he had been focused on talking to victims’ family members and did not offer any new details on the status of the investigation.

Scott also called for the federal government to share more information with its state counterparts in the wake of the shooting. Although he did not specify how more sharing of information might have prevented the massacre, Scott said it was broadly important that federal officials share what they learn with local law enforcement — especially in immigration or refugee cases.

He referred to terrorist attacks in Paris in November that killed 130 people, saying that he told the federal government afterward, “Look, until you can tell me how you’re going to vet people, don’t send refugees into my state.”

Even though Mateen was born in New York, the shooting has fueled a resurgent debate on U.S. immigration policy. Republican presidential candidate Donald Trump called Monday for barring immigrants from areas of the world with a history of terrorism as part of a proposed temporary ban on Muslims entering the United States.

During his remarks Tuesday afternoon, Obama dismissed the suggestion from Trump and others that he use the phrase “radical Islam” when discussing attacks.

“What exactly would using this label accomplish?” Obama asked. “What exactly would it change? Would it make ISIL less committed to trying to kill Americans? Would it bring in more allies? Is there a military strategy that is served by this? The answer is, none of the above. Calling a threat by a different name does not make it go away. This is a political distraction.”

In his remarks, Obama was sharply critical of Trump’s comments about Muslims. During a speech a day earlier, Trump had accused American Muslims of harboring terrorists and accused them — without evidence — of knowing about the attackers in San Bernardino, Calif., and Orlando, and not speaking up to stop them.

Trump has rejected calls for more gun-control laws in the wake of the shooting. Obama, as he has before, again said Tuesday that the country could do more to reduce gun violence.

The political fallout from Orlando also reverberated on the world stage. U.N. High Commissioner for Human Rights Zeid Ra’ad al-Hussein called on U.S. authorities to adopt “robust gun control measures.”

“It is hard to find a rational justification that explains the ease with which people can buy firearms, including assault rifles, in spite of prior criminal backgrounds, drug use, histories of domestic violence and mental illness, or direct contact with extremists — both domestic and foreign,” the top U.N. human rights official said in a statement.

At one of the many memorials after the massacre, the names of the dead were read aloud at a gathering on the lawn of Orlando’s main performing arts venue. In Paris, the Eiffel Tower was bathed in rainbow colors at night. Hours later, French President François Hollande warned of a “very large scale” terrorist threat facing his nation and the West.

“France is not the only country concerned, as we have seen again in the United States in Orlando,” he said.

Amid the public outpouring of grief and anger, the Florida attorney general’s office initiated a review into a proliferation of more than 100 requests on the money-raising GoFundMe site and others claiming to be seeking donations for victims and their families.

It is possible that all of the requests are legitimate, but “we just need to go through each one of them,” Attorney General Pam Bondi said.

Goldman and Berman reported from Washington. Zapotosky reported from Orlando. Julie Tate, Brian Murphy, David Nakamura and Missy Ryan in Washington, Zachary Fagenson in Port St. Lucie, Fla., and James McAuley in Paris contributed to this report.

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