A man was found dead in his apartment.

Answer At The Last Slide

When police came, they saw a cassette recorder in his left hand

Police also saw a gun in his right.

The police officer pressed the play button on the cassette.

In the tape, the man said, “I can’t live any more. I don’t have anything else to live for, I’m done!”

And then the clear sound of the gunshot.

And then the sound of gunshot. As soon as the cassette ended,

The officer knew it was not a suicide but a murder.

How did he come to this conclusion?

    ANSWER If it had been a suicide, how is the cassette recorder playing from the start?  Someone else rewind the tape and kept it there.