Solution:

Hhe hung herself using big Ice slabs , which are now now melted and hence puddle of water.

Solution:

Number 3

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

Solution:

Ruppell's vulture generally found on high altitude and Mr. smith was on the plane. The vulture hit the plane and the plane got crashed.

Solution:

This is because Adam is a hangman by profession. Apparently, his wife has been sentenced to death and he had to do it with his own hands.

Solution:

It is possible that the man was a deep sea diver. Such divers must wear a pressurized suit to withstand the pressure in the depths of the sea. If it tears down accidentally, the person will die. But for a short period of time, the breathing apparatus can keep him alive.

Solution:

The person is leaving hospital after visiting his wife. His wife is on a life support system. The elevator has stopped due to the power cut. If there was an emergency backup generator functioning well, the elevator would have also be running. It stopped in between means that the life system support has stopped as well.

Solution:

The Lady sitting in the chair has the detector attached to the back of her blouse.

Solution:

I have three theories based on which it can be either Murder, Suicide, or Accident.

Case1 : Its a Murder
Reason1: If it's suicide then a person must have waited for the Cigarette to end.
Reason2: Blood is spattered on the right side and the pistol is also on the right side. which seems pistol is planted at the end.

Case2 : Its a Suicide
Reason1. The lamp was switched off and glasses were removed which indicates she done writing(probably suicide note). The murderer does not care about switching off glasses or removing glasses.
Reason2: The blood was just on the wall at the height of a person. If it's a murder the blood must have been scattering around.
Reason3: Burning cigarette and alcohol indicated depression level which often is the reason for suicide.

Case3 : Its a Accident
It's must be an accident. The girl was writing using the pen and suddenly she heard a sound. She must have a gun for safety which she takes out of the security. As a preventive measure, she switched off the light so that she can't be seen in the dark. Also removed the glasses as they are of no use in the dark. After a while, she realized that it's just a sound. So to calm her down she drinks and also lights a cigarette. suddenly she slipped and try to hold stool but failed and forced her head into the wall and died.

Solution:

smoke inhalation

Solution:

In this picture, he saw another man. If you try to look near the right end of the picture, you will find a fan. Go down for the phone that is plugged on charge. Go further down and you will find a man's face. An eye is particularly visible. The man was hiding behind the bed when the husband arrived in her room. This made him believe that his wife was cheating on him.