Young Man Killed In East Boston Shooting Helped Save A Life In 2013

BOSTON (CBS/AP) —A young man who was shot and killed in East Boston last weekend once helped save another man's life.

Duncan Ketter, 21, of Boston, died Sunday night after he was shot in a car and dumped in the street, police said.

Thorus O'Brien, 18, of Brockton, was arrested Monday and charged with murder, armed robbery, and unlawfully carrying a loaded firearm.

O'Brien was ordered held without bail at his arraignment Tuesday in East Boston Municipal Court.  A 16-year-old was also charged with armed robbery in the same incident.

Prosecutors said the teen allegedly brought Ketter and a woman into a vehicle to exchange marijuana for cash.

"Unbeknownst to Ketter or the woman, however, O'Brien, was hidden in the rear cargo area of the vehicle,"  Suffolk County District Attorney's Office spokesman Jake Wark said in a statement.

"O'Brien allegedly revealed himself as the vehicle was in motion, producing a firearm and demanding marijuana from the woman and Ketter. When he met with verbal resistance, O'Brien allegedly fired, fatally injuring Ketter. The group allegedly threw Ketter and the woman from the vehicle onto the street."

Ketter helped save a man who fell on the tracks at North Station back in September 2013.  He jumped across two third rails to get to the victim.

A GoFundMe page was created to help for pay Ketter's memorial service.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)