This is mentally tasking question, especially as the picture is the only source of evidence you can rely on to determine the real killer in the picture.
Normally, for cases like this in reality, it’s usually hard to say until you check for the security camera’s, do a finger print check, match dna, question bar attendants as well as any guest who might help with the investigation.
But, not in this scenario. In this scenario, you have to test your own detective skills. Take a look at the pictures very well. Who is the killer? Who killed the girl among all the people in the restaurant?
For me, the answer should be number 4. When you look at the side of his clothes, you will notice that it is torn. Now, take a look again at the murdered victim on top of the roof. You will notice the same the piece that was torn from the cloth of number 4. Most people will say she tore it while struggling for her life.
Number 4 is also the closest to the scene of crime.
But, that’s just what is detectable from the pictures. In real life, the piece will have to be examined against the tear on number 4’s clothes.
Who do you think is the killer?