The defense rested its case Tuesday afternoon in the Noor Salman trial.
The case hinges on whether Salman, 31, knowingly helped Mateen plan the June 12, 2016, nightclub attack that left 49 people dead.
Salman's attorneys renewed their motion for acquittal Tuesday, but Judge Paul Byron denied it again.
Dr. Bruce Frumkin, a clinical psychologist who tested Salman last summer, was the last witness to testify Tuesday.
He testified that Salman has an IQ of 84 -- in the lower 14 percentile -- and thus she could be easily persuaded. He told jurors that "she's not the brightest of all people."
Frumkin said Salman is more vulnerable than the average person, which makes her “prime” for a false confession.
"False confession testimony occurs all the time," he said. "But it's for the jury to decide. I really can't say anything more."
The defense has always questioned the validity of Salman’s written confession to the FBI.
Frumkin said Salman’s confession isn't what it seems because of how immature she is and because she spent 11 hours being questioned after having slept only two hours.
Salman's attorneys wrapped up their case by reading a statement written by Neal Whittleton, a security guard who was working at the Pulse nightclub during the massacre.
Whittleton said a man, who he later realized was Mateen, asked if he was working security and was trying to see if he had a gun.
During cross examination, prosecutors pointed out that more risk factors and a low IQ could mean she's capable of giving a true confession.
Prosecutors didn't call rebuttal witnesses, and the jury was dismissed Tuesday morning.
"I think today really poked a lot of holes in the strongest piece of evidence that the government has leaned upon, which has been the confessions," said Susan Clary, a Salman family spokeswoman. "It's up to the jurors now."
Abdallah Salman, Noor Salman's uncle, said Tuesday that he believes his niece has received a fair trial so far.
"In the beginning, I said, 'Oh, it's gonna happen in Orlando, where the crime happened. It's gonna be hard,'" he said. "But I don't know. I have faith in the jury."
Closing arguments are scheduled to begin at 9 a.m. Wednesday. Jurors could begin deliberating the case as soon as Wednesday afternoon.
Salman faces life in prison if convicted.
WATCH LIVE: You're the Jury: the trial of Noor Salman
WATCH LIVE: Join the conversation with Eyewitness News 9's Greg Warmoth and legal analyst Bill Sheaffer as they recap today's events in the trial of Noor Salman, widow of Pulse nightclub gunman Omar Mateen. https://at.wftv.com/2IaNk3TPosted by WFTV Channel 9 on Tuesday, March 27, 2018
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