He shot himself during a fit of depression.

他一时心灰意冷，开枪自杀了。

《牛津词典》

To this day, it's unclear whether he shot himself or was murdered.

直到今天，他是自杀还是被谋杀仍然不清楚。

《柯林斯英汉双解大词典》

When they confronted the killer, he shot himself in the head.

于枪手对峙时，他朝自己脑门开枪了。

youdao

He shot himself to death in nineteen sixty-one, just as his father had years earlier.

VOA: special.2010.04.09

His family do not believe he shot himself and think horseplay or an accident could have been the cause.

BBC: Huddersfield soldier's inquest records open verdict

Initial indications are that he shot himself, but police are continuing to investigate, said Erwin Hetger, the regional chief of police.

CNN: Witness: Teacher 'sacrificed herself for student'

The note was found in Vincent's pocket after he shot himself.

ECONOMIST: The story of Vincent van Gogh