Authorities were searching for a man accused of stabbing another man at a Metro station in Norwalk.
Metro officials initially reported two men fighting on the platform of the Metro Green Line Norwalk station just before midnight on Wednesday, according to the Los Angeles County Sheriff's Department Transit Services Bureau.
Officials said one man took out a knife and stabbed the other in the torso before fleeing the scene.
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The victim was transported to a hospital in critical but stable condition.
Investigators are reviewing surveillance video from the site.
The Metro Green Line Norwalk station's east entrance was temporarily closed during the investigation. Metro was supplying shuttles for passengers traveling between the Norwalk and Lakewood station.
The station's east entrance remained closed as of 10 a.m., according to Metro.