Lots of trial and error required. Just use Google Lens, prepare your patience, and you'll have the answer in no time.
[Link](https://github.com/still-in-beta/CTF_Writeups/tree/master/2020/fword/Tracking_A_Criminal)

Original writeup (https://github.com/still-in-beta/CTF_Writeups/tree/master/2020/fword/Tracking_A_Criminal).