Solution:

As shown in solution picture, flip the first number and stack on the second number, you will get fish eight and triangle respectively.

Solution:

10.

Explanation:
Most of the people will give the answer as 6 or 3.
But the total number of holes are ten.
> 1 hole for the neck.
> 2 holes for the arms.
> 1 hole for the torso.
> 3 torn holes in the front.
> 3 torn holes in the back.

Solution:

12

Solution:

As marked in the solution picture, all men in the background have the same face.

Solution:

Murder.

Explanation:
1. There are signs of the struggle in the room as the clock is broken.

2. Two water glasses in the room indicate the presence of two people which also suggest that the killer is known to the victim.

3. There are a book and a pen on the bed which indicates that the dead person was reading and a suicide note was written from another pen which seems to be planted.

4. The man crutches are too far from the man.

Solution:

I Over Ate

Explanation:
Check the mathematical solution on the image below.
Also, 8 in 2018 resembles a fat person.

Solution:

Two right foot :-)

Solution:

The hidden cat is circled below.

Solution:

This riddle is perspective riddle where reader perspective determines if it's a murder or suicide.

A) Evidence suggests its a Murder
1. There are many signs that suggest struggle in the room.

2. The dead man seems to be left handed as all the essential things like the glass of water, the laptop is placed on the left-hand side and the murderer not knowingly that man was a left-handed placed gun on the right side.

3. We can see a man running in the background and probably run after opening the window.

B) Evidence suggests its a Suicide
The guy was frustrated and bankrupt(In the picture we can see some sort of financial data which going down like anything). He got drunk. and smacked the bottle into the wall with frustration and threw everything on the floor.
He then writes a suicide note and placed it on the table.
Pulls out a gun and shoot himself.
Note: Also about the man running, fingerprint and man running direction does not match

My perspective answer: Its a murder.

Solution:

Number 3

Explanation:
Since it's a ladies bathroom, so only ladies can enter the bathroom and hence most likely the killer.