If you aren't certain whether you should make the call, make the call. The person on the other end will listen. The person who answers will be able to put you in touch with the right officials in the place where you live. But there is another way to protect a child who is being hurt. If the child is not removed, the person who is hurting the child can be.
Someone has the authority to get the person committing the crime out of the house.
That is the police department. If you know that a crime is being committed against a child, you can call 911 and report it. In some cities, the police are enlightened and alert about the abuse and torture of children, and will react quickly and professionally. If you are convinced that a crime against a child is being committed, don't allow the person who answers the 911 call to tell you to go somewhere else. Don't hang up until you know someone is looking into what you have called about.