Allegations Brad Pitt was abusive on a private plane last week relate to the actor's treatment of his 15-year-old son, sources say, as the FBI continues to gather information before determining whether to open an investigation.
FBI spokeswoman Laura Eimiller said the agency hasn't made a decision on a formal investigation into what occurred on a plane ferrying Pitt, his wife Angelina Jolie Pitt and their six children.
Several news outlets have reported that a child welfare agency in Los Angeles is investigating the wellbeing of the children, who range in ages from 8 to 15.
Sources familiar with the allegations say the child welfare investigation centres on Pitt's conduct towards his son Maddox, 15, during an argument on the September 14 flight.
No law enforcement agency responded to the plane when it landed in Minnesota after the incident.
Amara Suarez, a spokeswoman for the Los Angeles County Department of Children and Family Services, said the agency could not confirm whether it was investigating Pitt or the wellbeing of the former couple's children.
Jolie Pitt filed for divorce on Monday and her lawyer released a statement the following day saying she came to the decision "for the health of the family". She listed their separation date as September 15, the day after the alleged plane incident, and the actress is seeking sole custody of all six of the children.
Pitt and Jolie Pitt - known as "Brangelina'" - were together for 12 years but only wed in August 2014.
Their six children include 15-year-old Maddox, 12-year-old Pax, 11-year-old Zahara, 10-year-old Shiloh, and 8-year-old twins Knox and Vivienne.
This is the second marriage for Pitt, 52, who was previously wed Jennifer Aniston. It's the third for Jolie Pitt, 41, who was previously married to Billy Bob Thornton and Jonny Lee Miller.
