The widow of the gunman who killed 49 people at a gay nightclub in Orlando has been acquitted on charges of lying to the FBI and helping her husband in the 2016 attack.

Noor Salman, 31, began sobbing with joy when she was found not guilty of charges of obstruction and providing material support to a terrorist organization, WKMG reported.

Salman was married to Omar Mateen when he attacked the Pulse nightclub. Police killed him after the massacre.

Prosecutors said Salman and her husband scouted out potential targets together — including Disney World’s shopping and entertainment complex — and she knew he was buying ammunition for his AR-15 in preparation for a jihadi attack.

She knew he had a sick fascination with violent jihadi videos and an affinity for Islamic State group websites and gave him a “green light to commit terrorism”, prosecutors said.

Defence attorneys described her as an easily manipulated woman with a low IQ saying Salman, who was born in California to Palestinian parents, was abused by her husband who cheated on her with other women and concealed much of his life from her.

Attorney Charles Swift argued there was no way Salman knew Mateen would attack the Pulse nightclub because even he did not know he would attack it until moments before the shooting.

His intended target was the Disney Springs complex, prosecutors said.

“It’s a horrible, random, senseless killing by a monster,” Mr Swift said during closing arguments. “But it wasn’t preplanned. The importance to this case is that if he didn’t know, she couldn’t know.”

Salman’s statement to the FBI in the hours after the attack appeared to play a key role in the case.

In the statement, Salman said over “the last two years, Omar talked to me about jihad”.

She claimed her husband did not use the internet in their home, but he did, prosecutors said.

Salman told investigators Mateen had deactivated his Facebook account in 2013, but they found he had an account up until the month of the shooting — and was friends with his wife.

She said her husband only had one gun when he had three, and he was not radicalised, they said.

Mateen had pledged allegiance to the Islamic State group before he was killed.

Salman also advised Mateen to lie to his mother when she inquired about his whereabouts on the night of the shooting, prosecutors said.

Charles Swift, defence attorney for Noor Salman, pacing outside Orlando Federal Courthouse (Red Huber/Orlando Sentinel/AP)
Charles Swift, defence attorney for Noor Salman, pacing outside Orlando Federal Courthouse (Red Huber/Orlando Sentinel/AP)

Defence attorneys said the FBI coerced Salman’s statement and she signed it because she was tired after extensive questioning and feared losing her young son. They fought to have it thrown out.

Jurors asked to review the statement more closely a couple of hours into their deliberations and the judge obliged, printing off copies for them.

During the trial, prosecutors said Mateen, who was born in New York to Afghan immigrants, intended to attack Disney World’s shopping and entertainment complex by hiding a gun in a stroller but became spooked by police and instead chose the gay club as his target.

Assistant US Attorney Sara Sweeney showed surveillance video of the Disney Springs complex that captured Mateen walking near the House of Blues club in the hours before the Pulse attack.

In it, he looks behind him at police officers standing nearby before deciding to leave.

“He had to choose a new target,” she said.

Salman’s attorney took the jury through the hours of her life before the attack.

She called a friend and her uncle in California, saying she was coming to visit and Mateen would be joining them.

She talked with her in-laws, ate at Applebee’s and texted Mateen. He did not respond. She later went on Facebook, read a book and then texted Mateen again.

“You know you work tomorrow,” she wrote.

He responded: “You know what happened?”

She replied: “What happened?”

Then he sent his last text: “I love you babe.”

Salman did not testify in her defence.