Allison Guerriero, the woman whose affair with disgraced FBI agent Charles McGonigal helped expose his covert work for Russian oligarch Oleg Deripaska, has died suddenly at her home in Boynton Beach, Florida. She died on the evening of 27 August, hours after posting a flurry of messages on X criticising the FBI, having spent years publicly campaigning against McGonigal and other senior bureau figures following their 18-month affair. Her death matters as the latest twist in a case that saw McGonigal, once head of FBI counterintelligence in New York, jailed for secretly working for a sanctioned Russian oligarch.

Police say there are currently no signs of foul play, though the investigation remains open and officers are awaiting the medical examiner's findings. Guerriero, 52, was found at her apartment after officers were called at 8.03pm; her father, Bill, 80, said he had not yet received a cause of death and was awaiting the autopsy report, insisting an accident was possible. Friends including Roger Stone said she had seemed in good spirits and was helping with research shortly before she died, while she was also known to have battled cancer and severe injuries from a past fire. McGonigal, 58, is serving six years in federal prison; Guerriero had long maintained his sentence was too lenient.