As murky rumors continue to swirl around the sudden split of Hollywood A-listers Brad Pitt and Angelina Jolie, the FBI has confirmed that it is gathering information surrounding an alleged incident involving Pitt and his children aboard a private plane Sept. 14 – the day before the couple officially separated.

“The FBI is continuing to gather facts and will evaluate whether an investigation at the federal level will be pursued,” FBI spokeswoman Laura Eimiller told The Washington Post. She declined to comment on how the FBI was notified of the alleged incident – because it occurred on a plane, it falls under the FBI’s “special aircraft jurisdiction.”

But beyond this confirmation, the details about what – if anything – happened seem far from clear. In her divorce filing Monday, Jolie Pitt cited only “irreconcilable differences” as the reason for the split, and listed Sept. 15 as the date of the couple’s separation. Her attorney later said in a statement that her decision to divorce was made “for the health of the family.”

TMZ was first to report on the episode that allegedly occurred during a private flight last week – offering vivid details and citing anonymous sources. TMZ stated that the incident was reported anonymously to authorities by a witness who was either on the plane or at the airport where it landed in Minnesota.

But those allegations have not been confirmed by any official on the record. On Thursday, the Los Angeles Times cited an unnamed law enforcement source who claimed the Los Angeles County Department of Children and Families was investigating Pitt; but the department itself has consistently declined to confirm whether or not an investigation is underway, citing confidentiality protocols.

Meanwhile, the Los Angeles Police Department has forcefully denied claims that it was investigating any complaint against Pitt: “LAPD is not handling any reports or allegations into child abuse for Mr. Pitt,” spokeswoman Jenny Houser told the Los Angeles Times.

Authorities in Minnesota confirmed that Pitt was on a plane that landed in International Falls, but said that law enforcement was not notified of any problem on the flight and was not called to the airport.

“There’s no incident whatsoever reported to law enforcement,” Koochiching County, Minnesota, Sheriff Perryn Hedlund told The Associated Press.

In her divorce filing, Jolie is seeking sole physical custody and joint legal custody of the couple’s six children: Maddox, Pax, Zahara, Shiloh and twins Knox and Vivienne. Jolie and Pitt, who first became a couple in 2005, were married at a French chateau in 2014.

In brief public statements, both actors have said that their primary concern is for their children, and have asked for privacy as their divorce unfolds.