femur spiral fracture

My son suffered a spiral fracture to his left femur. He was in a spica cast for 6 weeks. My question is this...
The accident happened at day care. The day care provider claims he was sleeping in a pack and play and she heard a boom and he tipped over the pack and play and fell out of it.  My son was not walking at the time.  He was sitting up but not pulling up. He was almost 11 months old.  The case is now under a criminal investigation which has been ongoing since october.  Do you think a child this age could tip over a pack and play  and if you do believe that could happen do you think a spiral fracture to the femur could have some how occured.  

[MImom0608]

I think it would depend on the weight of your child and how old the pack and play was.  Was it set up on an uneven surface?  When my daughter was 11 months she was walking and into everything.  She would pull on her pack and play and rock before that but it never tipped over.  I also used to gently rock it to calm her when she was using it as a bassinet.  Again nothing ever happened.  I dont know what could cause the break, but I don't believe a child who wasnt pulling up could knock it over.