Evening time

I was returning home from the chamber later in the evening,' the doctor began. 
"The snow is falling and the cold is increasing for the past few days, so I am not doing the chamber anymore at night. 
And his house is on my way back. 
Once I thought, go in and have some coffee. 
I could see from the street that the light was on in his study room. 
I walked along the lawn. 
We had to step carefully because of the frozen snow. 
I went to the window and wanted to take a peek to see what was going on. 
Due to the accumulation of ice, the interior was not well visible. 
I removed the ice with my gloves and saw that he was lying face down on the reading table.

"Then what did you do?"

Not understanding what had happened, I hurried forward and pushed the door and entered. 
Only the table lamp was burning in the study room. 
I lit another lamp in the room. 
I saw that the back was stabbed. 
No knife. 
Blood is oozing from the wound. 
Then I called you at the police station.

"Well done," said the police officer. 
"But I am sorry to have to put you on the suspicion list. 
You need to interrogate a little more.'

Why? 
Would I have informed you if I had killed?' The doctor asked excitedly.

"But we never once said that you killed or were involved in murder," said the police officer calmly.

So why doubt? 
Why should be questioned?'

"Because you lied."

The secret