The FBI has confirmed they are investigating a child abuse incident involving actor Brad Pitt and one of his sons.
The incident occurred onboard a private jet flying from France to Pitt's home in Los Angeles on September 14, 2016.
According to a People magazine source, Pitt was drinking heavily when he got into an argument with his estranged wife, actress Angelina Jolie.
One of the couple's sons, believed to be Maddox, 15, stepped in to defend his mother.
Jolie adopted Maddox from a third world country before she met Pitt.
"There was a parent-child argument which was not handled in the right way and escalated more than it should have," a source told People magazine.
Pitt, 52, allegedly got "verbally abusive" and "physical" with the boy, but the source denies reports that Pitt slapped him in the face.
"He is emphatic that it did not reach the level of physical abuse, that no one was physically harmed. He did not hit his child in the face in any way. He did not do that; he is emphatic about that. He put his hands on him, yes, because the confrontation was spiraling out of control."
The FBI is involved because the incident happened on a private jet in mid-flight, which is special aircraft jurisdiction.
"The FBI is continuing to gather facts and will evaluate whether an investigation at the federal level will be pursued," the FBI said in a statement to PEOPLE magazine.
Jolie, 41, and the couple's five other children were present and witnessed the incident, which is also being investigated by the L.A. County Department of Children and Family Services..
The Los Angeles Police Department confirmed it is not investigating a child abuse incident involving Pitt, a spokesperson previously told PEOPLE.
Jolie filed for divorce on Monday, Sept. 19, citing "irreconcilable differences" and Pitt's explosive anger as factors.
She is seeking sole physical custody of the couple's six children – Maddox, Pax, 12, Zahara, 11, Shiloh, 10, and 8-year-old twins Knox and Vivienne. She is requesting visitation for Pitt, but she did not request spousal or child support.
The date of the couple's separation was listed as September 15 – the day after the alleged child abuse incident on the plane.
Pitt retained high-powered family law attorney Lance Spiegel, who represented Michael Jackson, Russell Simmons, and Charlie Sheen in the past.
A source said Pitt is concerned that Jolie wants full custody so she can move to the Uk with the children on a permanent basis.