Vincent Van Gogh - Suicide or Murder?

Consider that he was shot in the abdomen, crawled back to where he was living, got into bed. His brother Theo came. Vincent died after 3 days of suffering. As far as I know, he never mentioned suicide to his brother to whom he wrote letters almost daily. This would argue against suicide. He did write about feeling that he was an outcast. If suicide, it is not surprising that he would take his life in a way that caused him to suffer. He usually took a gun when he painted outdoors. He was shot with his own gun. He was taunted and verbally abused in the town of Arles. His behavior was bizarre. He was known to argue vehemently with townspeople. 

His description of himself: What am I in the eyes of most people — a nonentity, an eccentric, or an unpleasant person — somebody who has no position in society and will never have; in short, the lowest of the low. All right, then — even if that were absolutely true, then I should one day like to show by my work what such an eccentric, such a nobody, has in his heart. That is my ambition, based less on resentment than on love.

Three boys, probably teenagers were in the field with him when he was shot. Perhaps he got into an argument with them that ended with one of them shooting him.

He wrote beautiful letters to his brother. Here are a few of his quotes that struck me:
It is good to love many things, for therein lies strength, and whosoever loves much performs much, and can accomplish much, and what is done with love is well done. ”

“I don't know anything with certainty, but seeing the stars makes me dream. ”

“It is with the reading of books the same as with looking at pictures; one must, without doubt, without hesitations, with assurance, admire what is beautiful.

“I would rather die of passion than of boredom.”

 “Always think that the best way to know God is to love many things. ”

“I put my heart & soul into my work and have lost my mind in the process.”

“What would life be if we had no courage to attempt anything? ”
Whether it was suicide or murder, his last painting Crows over Wheat Field shows that he had death on his mind. The vanishing point in a painting usually is in the background where all lines converge. In his last painting this is reversed. The paths in the wheat field converge not only at the foreground but even more so, the point at which the artist was standing when he painted it. In other words, Vincent was the vanishing point. Was he saying that he was about to vanish?