Our sources say ... the L.A. County Dept. of Children and Family Services initially focused on the plane incident in which Brad allegedly struck 15-year-old Maddox.
Our sources say, through various interviews with family members, DCFS has now expanded its investigation to other alleged incidents, including interactions between Brad and Angelina which were allegedly witnessed by 1 or more of their 6 kids.
The Angelina sources say some of the children have been fearful around Brad, and Maddox in particular has problems with his dad. We're told the meeting Brad had with Maddox last week ended quickly because Maddox didn't want to be there.
None of our sources would say if the DCFS interviews turned up anything that would cause the agency to take action related to custody.