The stabbing was reported at 1:16 p.m. near Wall Street and Olympic Boulevard.
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Los Angeles Police says the man got into some sort of altercation with two other people, a man and a woman, when the man pulled out a gun and stabbed the victim multiple times.
The victim - who was identified only as a man in his 50s - was pronounced dead on the scene.
The two suspects fled the scene, but were apprehended shortly after.
It's unclear what led to the altercation. The incident remains under investigation.