Hard situation puzzles

A couple find a man's corpse on the beach. The corpse is under an umbrella and has a knife on his back. There are no signs of violence and no traces of blood. The autopsy reveals that the man died of natural causes.

He died because he mixed up the colors.

Jimmy hid a treasure but when he wanted to recover it, he was not able to.

Paul comes home tired. He goes to his room and turns off the light to sleep. After a while, feeling uneasy, he turns on the light and looks around. He turns the light back off and tries to sleep again. After repeating this several times, he takes a look under his bed and finds a dead body.

A man goes to the doctor to get the results of some previous tests. The results do not show up any health issues. However, he commits suicide shortly after the visit.

A man enters in a restaurant, eats and gets up from the table crying uncontrollably.

Before going to bed, the woman hides her shoe in the safe. What for?

A man, who was examining some school, noticed that any time a teacher was asking a question, lots of pupils were ready to answer. Moreover, every time the teacher was choosing another person and the answer was always right.

If the wind hadn't blown so strongly that night, Angela would still be alive.

A woman starves to death despite being surrounded by food.

A man is lying face down, dead, in the desert, with a match near his outstretched hand.

A car driver causes an accident when he crashes into a bike, as he was making an unexpected turn at a crossroad. When the policemen arrive, another man gets arrested. The one who was driving is carried home.