The reasoning for suspect 3 makes no sense. Point #1 would make them more suspicious. Point #2 doesn't do anything to differentiate between men and women. Point #3 is ambiguous.

@Adam for a women to kill another women with knife in washroom without any noise and struggle? is it even possible?

This is an issue of strength, it has nothing to do with your sex. I don't know how you can determine someones strength based off of an image. Even then the motion required to pull off such a stunt would be challenging for a strong person. Although this whole issue can be avoided if you consider that it is possible the victim was in a weakened state

@Adam it is mentioned in the image that the victim is in weakened state? as you can see in the image both women are of normal size, yes you can determine the strength by looking at their body. go with the clues in the image don't make your own assumption, in the case women was not killed she did suicide she was stressed out .... are your happy now? I mentioned the clues in the image... the man in red shirt gave the most of the clues...

A weakened state normally isn't visual. The victim could've been ill, been inflicted with a medical condition, been drugged or been caught off guard. The men are also of normal size in the image. How are we supposed to know who would win then? It is still entirely possible that suspect 3 did it

This is why image puzzles like this are normally too-broad or primarily opinion based

@Adam, the image gave you simple clues, this is visual puzzle where you need to find the clues from the image and tell who is the victim. but what you are doing is making your own assumptions and stories you are wrong about it... if you do those assumptions you will ruin the riddle. the assumptions you are making will not help to solve the puzzle but you are making it too broad... it is not the puzzle which is broad, it is you who is making it broad...

I am not making anything broad, it is the puzzle itself. Are we to assume that it is mandatory for someone solving this to assume that suspect 3 couldn't do it because they don't have large bulky muscles?

@Adam I have mentioned lot of points for suspect 3 and suspect 4... please go through all of them and counter it with your answer instead of making fault stories...

@SayedMohdAli I've already countered all of the points for suspect 3. Just because suspect 4 is likely doesn't mean that suspect 3 also couldn't have done it. I also cannot post an answer if the question is currently on hold

@Adam okay tell me your answer.

and if you have a better answer then why you didn't posted it is put on hold recently

@SayedMohdAli We aren't supposed to answer questions which are likely to be put on-hold since it gives unwanted attention to unfinished/negative questions

Theoretically if I did post an answer it would be along the lines of "anyone could've done it however if you want to argue probability then it is safe to say that suspect 3 and suspect 4 are both equally likely due to the circumstances in this scenario"

It doesn't matter what the intended answer is. If it is reasonable for many answers to exist then the question is either "too broad" or "primarily opinion based". The solver shouldn't be put into the position where from their point of view it is impossible to arrive at a single, conclusive answer

adam I want your answer, I will take screenshot and discuss the matter in stack exchange site, so you don't worry

if you don't have a proper answet to the question that means you are wrong...

Are you really sure that you want the answer? It would be overly general and possibly harmful to your question. It also could be vaguely classed as "a duplicate" since the two top answers already discuss suspect 3 and 4 which is what my answer would focus on after broadly discussing everything