Apply force to ragdoll after enemy death

When enemies die in my game they are replaced with ragdolls.
I want to apply a force on the ragdoll’s body part where the killing bullet of the live enemy hits.
The problem is that transform.FindChild can’t find the ragdoll’s body part that were hit when he was alive.
How can I find the right body part without recursive function?

Insantiate with the function

OnDeath(){

}

and have the creation be in the variable so you have it saved as a transform then you can instantiate a script or apply before you die
Var.rigidbody.AddForce;