The father of the 29-year-old who killed 49 people at an Orlando nightclub in the summer of 2016 was an FBI informant who came under scrutiny himself after investigators found receipts for money transfers to Turkey and Afghanistan in the wake of the mass shooting. The revelation came in documents filed by attorneys for the shooter's wife, Noor Salman, who is on trial in Orlando on allegations that she aided and abetted her husband's attack and obstructed law enforcement's investigation into it. Salman's trial has been underway for weeks, but defense attorneys argued that they were not informed until Saturday of the father's work for the FBI. That, they argued, is grounds to dismiss the charges. Seddique Mateen - the father of Omar Mateen - was an FBI informant at various points between January 2005 and June 2016, court documents say. Salman's attorneys argued in court filings that if they had known of Seddique Mateen's work for the bureau, they might have explored ... whether the FBI's interviews with Salman were an attempt at evading the negligence they exercised with their own informant," and whether their "unwavering focus on Noor Salman, rather than Seddique Mateen, could have been designed to find a culprit other than the father." The FBI has previously come under criticism for investigating Omar Mateen for 10 months starting in 2013 and ultimately concluding he was not a threat.