The Case Of LOCKER NO. 42 - Part 1

A blood-stained letter is sent to the Bureau. Closer inspection reveals that the key opened one of the lockers in a local bank. The team rushes to the bank to find out more about this mysterious key. They open the locker and find 9 Lakh Rupees. This makes the case even more complicated. Why was a blood-stained key sent to the department? What happened to the owner of the safe?