S₁: The detective walked into the dark room alone.

S₆: At once he saw the disorder and confusion in the room.

P: It was later that he found the gun lying under a chair.

Q: First he felt for the switch and turned on the light.

R: The furniture was smashed and the curtains torn.

S: He carefully picked up the gun making sure not to smudge the fingerprints.

The proper sequence should be

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…

In this question each  items consists of a word in capital letters, followed by four…