Easy: Troti's Case

It was an average day, Troti ( The ruler of the Inspectors ) was walking down the street. He heard a gunshot and ran towards it. A nearby restaurant owner had gotten shot.

He ran inside, the owner left a suicide note on top of the gun, which was on the table. He had a bullet wound in his head

The cops came in, and said it was an obvious suicide, his reason was because his restaurant was failing and about to be bankrupt. They had his suicide note, in handwriting that looked like his. But Troti wasn't sure.

What changed his suspicion about the suicide?

If the owner of the restaurant had shot himself in the head, he would have no time to put the gun and the note on the table, and if the note was already written and placed, it would be under the gun, not on top of it.