Solution:

mother

We know from (3) that the youngest person was not the victim, from (4) that the youngest person was not the helper and from (6) that the youngest person was not the killer. The youngest person can only have been the witness therefore. If we make up a chart there are now three possible combinations:

Oldest person (father) H H M

Next to oldest (mother) V M H

Next to youngest (son) M V V

Youngest (daughter) W W W

(H = Helper ; V = Victim ; M = Murderer ; W = Witness)

We can work out from (5) that the father was the oldest, from (2) that the youngest person must have been the daughter. Therefore the next to the youngest must have been the son and the next to the oldest, the mother.

Solution:

Dabid is the killer

drawing room(D) , art room(a) , bed room (b) , ice-cream room (i) , desk room (d)

Solution:

She was hoping that the guy would appear at the funeral again.

Solution:

Frost forms on the inside of the window, not the outside. So shweta could not have wiped it off to discover Mr.Ankit's body.

Solution:

Jason Kumar

The number on the calendar was written in a hurry.Sherlock matched the written number with the months of the year.
So the B was an 8, thereby giving us 7-8-9-10-11: July, August, September, October, November.

Use the first letter of each month and it spells J-A-S-O-N.

Solution:

Wayne Rooney stole socks
Danny welbeck stole shoes
Robin Persie stole football

Solution:

Newspaper delivery man was the murderer because of absence of Wednesday and Thursday missing newspaper.
This indicates he already know that there is no one to read it.

Solution:

Bill. If you read the message upside down, you'll notice that the numbers resemble letters and that those letters form legible sentences. The message is 'Bill is boss. He sells oil.'

Solution:

Eggs

Dinosaurs laid eggs long before there were chickens

Solution:

JUPITER