Call Child Protective Services with the Department of Social Services and report your concerns. They will investigate as to whether the mother poses a danger to the child if they have certain evidence to prove the abuse. A restraining order is normally only worth the paper it is is written on. You need to get CPS and law enforcement involved if you expect any assistance.
The information provided in this answer does not create an attorney-client relationship. If you are interested in his legal services, feel free to call Chris at (303) 409-7635 at his law office in the Denver Tech Center. All initial consultations are free of charge.
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