Which alphabet is a part of our body?

One evening there was a murder in the home of a married couple, their son and daughter. One of these four people murdered one of the others. One of the members of the family witnessed the crime.

The other one helped the murderer.

These are the things we know for sure:

1. The witness and the one who helped the murderer were not of the same sex.

2. The oldest person and the witness were not of the same sex.

3. The youngest person and the victim were not of the same sex.

4. The one who helped the murderer was older than the victim.

5. The father was the oldest member of the family.

6. The murderer was not the youngest member of the family.

Who was the murderer?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

What always comes into a house through the keyhole?

Do you know who was buried in John's tomb?

Can you count the number of triangles in the given figure?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.