Murder Witness

I am lucky. My office overlooks a beautiful park. The views are spectacular all year round. Until today...
Today a murder was committed just yards from my office window. It happened five minutes after I arrived. A young woman it seems was jogging in the park when she was brutally stabbed to death....
The noise of the fax machine, telephones and the chatter of colleagues drowned out any screams, if indeed she did scream. I heard nothing.
I was either too busy or too lazy to open the blinds before starting work, therefore I saw nothing...
The police are searching for witnesses - the park is usually quite busy at 8.30 in the morning. Surely somebody must have seen or heard something? ....or are they , like me, relieved in their own little way that, for whatever reason, they were not witness to a murder....