Recent NYC Subway Violence Leaves Multiple Victims Injured and Dead.

An 18-year-old straphanger was fatally stabbed on a Brooklyn subway train after his friend pulled the emergency brake, causing a delay. The attacker, Mark Smith, got into an argument with the victim and then allegedly stabbed him in the abdomen. Smith turned himself in and has a criminal record. The incident was not captured by surveillance cameras, but witnesses identified Smith as the attacker. The motive was described as a "stupid kid prank." The incident comes amid a recent uptick in major crimes on the NYC subway system.