ORLANDO, Fla. -- Attorneys for the widow of Pulse nightclub gunman Omar Mateen are calling for a mistrial after they say prosecutors revealed that Mateen's father was an FBI informant. CBS affiliate WKMG- reports that prosecutors sent an email on Saturday that stated Seddique Mateen was a confidential FBI source from 2005 until 2016, according to a motion filed by the defense.

Omar Mateen's widow, Noor Salman, is on trial in federal court on charges of aiding and abetting her husband, obstruction of justice and lying to federal agents. If convicted, she could get life in prison.

Her husband killed 49 people and injured at least 68 others when he opened fire inside Pulse on June 12, 2016 before he was shot to death by police.

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WKMG-TV reports that the email sent by prosecutors stated that Seddique Mateen is also being investigated for money transfers to Turkey and Pakistan.

Seddique Mir Mateen, father of Orlando gunman Omar Mateen CBS News

Salman's lawyers allege the new revelation prevented them from investigating whether or not Seddique Mateen knew of his son's plans to attack the nightclub.

According to the motion, defense lawyers allege that the decision not to give Noor Salman a polygraph was possibly "based on the FBI's desire to implicate Noor Salman, rather than Seddique Mateen in order to avoid scrutiny of its own ineptitude with the latter."

"Mateen's father played a significant role in the FBI's decision not to seek an indictment from the Justice Department for false statements to the FBI or obstruction of justice against Omar Mateen" during its 2013 investigation into his alleged threats, the motion stated.

Meanwhile, attorneys in federal court Monday will try to convince jurors that Salman didn't help her husband as he prepared for the attack on the gay nightclub.

Federal prosecutors rested their case Thursday. Mateen and his wife exchanged text messages during the attack, according to evidence presented to a jury.

"I love you babe," Mateen wrote in his last text message at 4:29 a.m.