Judge took children away?? (Why?)?

[Peaches12]

A classmate kept bugging me on Facebook with friend requests. So I finally added her. She posted about how much she missed her children. (Ages 4 & 6). Later posted how the judge took her kids 8 months ago. She has not had contact with them since. Some one asked where they were she said foster care & she doesn't knows where.

What could she have done to have kids taken away, plus no contact what so ever??