My 1 year old LO got taken by my relative without permission

Hi, Would like to get everyone's thoughts on this. Yesterday, my wife and I were at work , and my 1 year old daughter was at home with my in-law. In the late afternoon, my older sister came to my home with my mum and took away my LO, and brought her back to her home. She informed my in-law but didn't inform us parents at all (not even a text). We were pretty mad that she came to take her niece without our consent. Her claim was that she already informed my in-law, which should be alright. But, I thought the right thing to do is to be asking/informing the parents first before taking the LO. What's your thought?