Find information on a Facebook account that is threatening my sister

Hi. I am a resident of Pakistan, Karachi. My sister has been getting threats on Facebook by a fake account of getting her pictures leaked to the public. The account has somehow stolen all her pictures on Facebook and Instagram and has edited them into inappropriate pictures. He is threatening to leak them to her entire friends list which he got access to as well somehow. I did reach out the cyber crime department in Pakistan but they just take too much time to respond, at least 4 months and we can’t wait that long. Can information on the fake account be extracted somehow? Information like the true identity of the person, or the area of his residence because he is definitely from Pakistan, and other similar information which may help us to file a complaint in the normal police department against the person behind these acts? I will provide all proofs and evidences of the threats and screenshots in private messages. I also take all responsibilities for this job. I am attaching the screenshot of the Facebook account that is threatening my sister.