SOLVE THE CASES IF YOU CAN

CASE-1

Authors note - please vote and please write your answers in comments.....and well these cases are really hard to solve , I shuffled it , let's see how's your brain , and I don't mind if you tell me to write the answers in the next page
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
While solving the cases think that you are police officer or a famous detective you are one of the capable officer/detective and everything depends on you so think deeper and answer it correctly

Case - 1 - who killed the man
A women came to you on Monday morning and asked you for help she told that her brother was dead yesterday so you
went to the house for investigation when you went to the house you saw the victim's wife
you went to the wife you wanted to ask questions but you didn't
because she was crying a lot so you didn't bother her and went to the sister
to ask questions you asked her where you were during the murder
she told you that she was handling a business deal in New York for 1 day
And then you asked her when did she leave she told on Saturday morning and
she came back on Sunday night at 8 o' clock
Then you ask her then how did she knew that her brother died yesterday??
she answered that the wife told her
you let her go and went to the house for investigating you didn't find anything
special then you went to the wife for questions ,you ask her where she was during the murder
she answered she was in her father's house for 2 day
then you ask when did she leave from here
she answered she left in Saturday at 2 pm and backed at Monday at 2 am
then you asked her that when did she reach her father's house
she told at 3 pm
and when did she leave from her father's house
she answered at 12 am
you asked her how long it takes to reach her fathers house from her house
she said it depends on what speed the driver takes the car
she also told that it takes usually 1 hour  when the driver drives the car in more than the speed of100 ,
Then you went to the driver and ask him in what speed did he drives the car
he answers 120
then you ask him that when he was driving to drop his ma'am in her fathers house what speed did he drove on?
he told 120

Think harder and write the answer who killed the man and how did you found it?? in comments
Its the 1st one and easy one

*************
Before continuing don't forget to vote