The suspect in a deadly nightclub shooting in Florida was the son of an FBI informat, court documents have revealed.

CBS News reports that attorneys for Pulse gunman Omar Mateen‘s wife Noor Salman are asking for a mistrial after prosecutors reportedly revealed that Mateen’s father was an FBI source from 2005-2016.

Mateen killed 49 people in the Orlando nightclub on June 12, 2016, before he died by police gunfire. Salman is facing charges of aiding and abetting, lying to federal agents, and obstruction of justice.

According to a motion filed by the defense, a member of the prosecution sent an email this past weekend stating that Seddique Mateen, Omar’s father, was a confidential FBI source, and also revealed that in 2012, he had been “seeking to raise $50,000-$100,000 via a donation drive to contribute toward an attack against the government of Pakistan.”

The motion, obtained by CBS affiliate WKMG, argues that the investigation into Salman’s alleged role was mishandled because the agency did not want to expose its relationship with Seddique Mateen and the allegations against him. Specifically, the motion claims, Salman was not given a lie detector “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.”

The attorneys reportedly argued that the timing of the disclosure meant that the defense team did not have an opportunity to investigate whether Mateen’s father was aware of his plans to attack the nightclub.

In 2013, Omar Mateen was investigated for making allegations against co-workers.

“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 reportedly states.

Salman’s attorneys are expected to present their case in court on Monday. If she is convicted, she could be sentenced to life in prison.