What does the below image rebus riddle means ?

Where do fish keep their money?

It is always ahead of me yet I can never see it. What is it?

I have eight fingers and two thumbs but I do not live. What Am I?

Can you place six matchsticks in a manner that each of the matchsticks is in touch with the other five matchsticks?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

There was a strange boy who was born before his father. How can this be possible?

What number should come in place of the question mark below?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?

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?