WASHINGTON — The FBI arrested the wife of the man who carried out a deadly terrorist attack in Orlando, Fla., and charged her with obstructing the investigation of the mass shooting, law enforcement officials said Monday.

Noor Salman, whose husband, Omar Mateen, killed 49 people and wounded dozens in an Orlando nightclub that was popular with gays, was also charged with aiding and abetting by providing material support, the officials said.

She was taken into custody by FBI agents at her home outside of San Francisco, where she had been living with her young son. Prosecutors had been weighing charges against her for months in the aftermath of the attack by her husband on June 12, 2016.

Investigators interviewed Salman for hours after the attack and came to believe she was not telling the truth about her husband’s plans to carry out the rampage.

A Justice Department spokesman said Salman would make her initial appearance Tuesday morning in federal court in Oakland, Calif.

In a separate development Monday, Turkish media said a gunman suspected of killing 39 people during a New Year’s attack on an Istanbul nightclub has been caught, the Associated Press reported. The suspect was captured in a police raid on a house in Istanbul’s Esenyurt district.

As in the Florida attack, the Islamic State had claimed responsibility for the Istanbul massacre.

The Justice Department’s decision to prosecute Salman, 30, ends part of the mystery that has surrounded her since the first days after the attack, when she became a central subject of the wide-ranging investigation on her husband.

“Noor Salman had no foreknowledge nor could she predict what Omar Mateen intended to do that tragic night,’’ said her lawyer, Linda Moreno. “Noor has told her story of abuse at his hands. We believe it is misguided and wrong to prosecute her and that it dishonors the memories of the victims to punish an innocent person.’’

The aiding and abetting, a terrorism charge, suggests that prosecutors believe that Salman helped him in some way — either before or after the terrorist attack.

The decision to charge her is not without risks for prosecutors. If the case goes to trial, prosecutors will have to contend with a jury that could be sympathetic to Salman, who said she was in an abusive relationship and living in fear.

In an interview last year with The New York Times, Salman said she had accompanied her husband to Orlando with their child once when he scouted the club but did not know the purpose of the trip.

On the day her husband drove to Orlando, she claimed he said he was going to visit a friend, named Nemo, who lived in Florida. But Nemo was not living in Florida at the time, a fact Salman said she did not know.

She also said she had no reason to suspect that ammunition he bought in the days leading up to the attack was to be used in the shooting, given that her husband was a security guard who frequently purchased ammunition.

On the day of the shooting, she bought her husband a Father’s Day card, expecting him to return that evening. Her lawyers believe that supports her story that she did not know about the attack.

During his rampage, Mateen used Facebook to pledge his allegiance to the Islamic State. President Obama has said that Mateen “took in extremist information and propaganda over the Internet and became radicalized.’’

Federal investigators do not believe that Mateen, who was 29, received any specific training or support from the Islamic State. Part of their inquiry has focused on whether anyone in the United States assisted in his plans for the attack.

There has perhaps been no figure more central to those questions than Salman, who grew up in an avocado-colored home in Rodeo, Calif., near San Francisco.

In Rodeo, on a diverse block populated by Chinese, Indian, Korean, and Mexican families, neighbors recalled a younger Salman as warm and kind.

Salman married Mateen in a ceremony near her childhood home in Northern California, a second marriage for both. After the wedding, Salman moved to Fort Pierce, Fla., where she and Mateen lived in a two-story condominium complex.

Their marriage in 2011 caused consternation among some of Salman’s relatives, mostly because of her Palestinian heritage and Mateen’s ancestral ties to Afghanistan. Salman said in the interview with The Times that her husband beat her repeatedly and verbally abused her.

Members of Mateen’s family, who have tried to shield Salman from public scrutiny, have said they believe she did nothing improper.

“She is shocked, that poor lady,’’ Seddique Mateen, Omar Mateen’s father, said in June 2016. “And she doesn’t know anything.’’

In 2014, federal prosecutors declined to prosecute Katherine Russell, the wife of one of the assailants in the Boston Marathon bombing on April 15, 2013. FBI agents believed she had made false statements to investigators and concealed knowledge of a crime.