Good job

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 mystery is how the police officer realized that the doctor lied," Maysha finished the story.

'Heh,' said Uncle Baltu in a sly tone. 
"I told the story of Bilet while sitting in Bangladesh. 
And I see no mystery here. 
The police have suspected, yes. 
Amani said that the doctor lied.

'I think I've got the secret,' said Tahjib.

'You can do that,' said Doltu Mama. 
'Since your elder sister has told the secret, you are telling it too. 
You read in class seven. 
So you think of the elder sister studying in the university, omniscient.

'Not at all,' protested Tahjib.

"Then tell me, what is the secret?"

'The doctor first said that he saw lights in the study room from across the street,' Tahjib began. 
'Then he said again that there was a layer of ice on the glass windows, so he couldn't see inside very well. 
That means coming close to where the window is