I saw this picture riddle online and have been cracking my brain pls where are the CSI experts Abeg, help us catch this murderer.

The woman (No 3) is the culprit. Reasons - 1. it is women's toilet (a man entering a ladies room would certainly raise suspicions). 2. the surprise on the waiter's face on seeing another woman at the table (the now deceased woman must have been sitting there before). 3. the woman was stabbed in the back (implying her back was turned towards the culprit, while she was using the washroom; were a man the killer, the victim would probably be facing him, possibly screaming too, the moment he enters).

Of course there's a little case against No 4 (missing table knife, stain (blood??) on the neck). However, the case against No 3 is stronger.