Noor Salman, the widow of the Pulse gunman, has been found not guilty.
After two days of deliberations, the federal jury found the 31-year-old not guilty.
Forty-nine people died at Orlando’s Pulse gay club during the horrific mass shooting in June 2016, when Mateen, who had pledged support for ISIS, opened fire on the crowd.
At the time it was the most deadly mass shooting in recent US history, though it has since been surpassed.
Mateen was killed in a shootout with the local police during the attack.
Susan Clary, the spokeswoman for Salman’s family, said outside the court: “We are so grateful to them, so grateful for their verdict.
“She can go home now and try to pick up the pieces,” she added, according to CNN.
“It’s Good Friday for everybody,” her uncle, Al Salman, said. “I want to say thank you, Lord.”
Orlando Police Chief John Mina, in a statement, said: “Nothing can erase the pain we all feel about the senseless and brutal murders of 49 of our neighbors, friends, family members and loved ones,” he said.
During the trial, prosecutors said she aided Mateen ahead of the massacre, then lied to the FBI in order to damage the investigation.
“This case is about what she knew and what she did,” Assistant US Attorney Sara Sweeney said.
“The defendant didn’t pull the trigger that night, but she did serve as a green light for her husband.”
On the other side, Salman’s attorneys argued that she was not an accomplice to Mateen’s crimes, but simply an innocent victim caught up in her husband’s lies and crimes.
“She doesn’t go to the mosque, she searches for Hello Kitty on her website,” Charles Swift said for the defence in his closing argument.
“We’re supposed to believe she had long conversations with Omar Mateen about jihads?”
Salman’s lawyers pushed for a mistrial – alleging that prosecutors failed to provide information to their client.
The defence alleged that Omar Mateen’s father Seddique Mateen was an FBI informant between January 2005 and June 2016 – details they claimed were concealed ahead of the trial.