What does this below rebus puzzle mean?

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

Find the next number in the series below

21 32 54 87 131 ?

Can you count the number of squares in the figure below?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

How many triangles are there on the puzzle below?

A bridge is about to collapse. There are four people P, Q, R and S on one of the sides. Before the bridge collapses, they want to cross it. Now since the bridge is too weak, it can only stand the weight of two people at a time. Also, it is night time and nothing is visible. They have just one torch with them.

Now P takes one minute to cross the bridge, Q takes two minutes to cross, R takes five minutes to cross and S takes ten minutes to cross.

The bridge will collapse in seventeen minutes. How will they be able to cross the bridge before it collapses?

Buy me, smell me or deliver me, I do not change.

Who am I?

Next Number in the Series,

5, 16, 49, 104, ?

If your uncle’s sister is not your aunt, what relation is she to you?