In freeing Mateen's widow, Noor Salman, from federal custody pending the trial, federal magistrate Donna Ryu cast doubt on the strength of the government’s case against her.
Salman was arrested in January and is facing two felony charges for allegedly aiding and abetting Mateen's "provision of material support" to the terrorist group ISIS and obstructing the investigation into the massacre.
“I find that at this time the weight of the evidence is debatable,” Ryu said. “All of the information provided by the government is hotly debated.”
The bulk of the government’s case relies on admissions Salman allegedly made toward the end of an interrogation that occurred during a 16-hour detention.
Federal prosecutors have said Salman was in the car with Omar Mateen as he cased three potential Orlando locations and that the couple spent some $25,000 using credit cards in the days before the shooting and made Salman the death beneficiary of Mateen's bank account. They’ve also said she created a cover story for him by telling his family he was going out for dinner with a friend.
“The alleged admissions may be vulnerable to constitutional attack,” Ryu said. The judge added that the strength of the government’s evidence beyond the admissions “is also debatable at this time.” And Salman's defense rebutted every argument of the government's allegations against her.
Ryu had ordered a psychiatric evaluation before deciding whether to grant bail. She said the exam supported the defense's claim that Salman "has some cognitive deficits that impair her ability to engage in abstract thinking."
Prosecutors did not provide enough evidence in court to keep Salman behind bars and did not establish clear evidence that Salman was violent or dangerous, Ryu said.
Salman's mother and uncle will serve as custodians and have offered up their houses and property as equity to secure her $500,000 bond. She will wear an ankle bracelet monitoring unit. Her uncle is responsible for monitoring and supervising Salman at all times.
Salman will not be immediately released from federal custody, giving prosecutors 48 hours to appeal the judge's ruling.
Under the conditions of her release, Salman will not be able to travel outside of California and Florida, but she can travel between the two states with advance approval.
While under house arrest, Salman cannot have her passport or have any travel visas issued and will not be permitted to own or carry a firearm or have one in the house.
Orlando Police Chief John Mina said he was "disappointed" that Salman would be released from federal custody.
"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," the chief said in a statement, adding, "I have full faith that she will ultimately be brought to justice."
On June 12, Mateen killed 49 people and injured dozens more when he opened fire in a popular Orlando nightclub.
Prosecutors allege that Salman "knew [her husband] was going to attack," and accuse her of lying to police and federal investigators.
Salman entered a not guilty plea to the charges at a hearing in January. In an interview with The New York Times in November, Salman said "I was unaware of everything," and “I don’t condone what he has done."
ABC News' Rachel Katz contributed to this report.