A New York City subway ride turned deadly for one rider after a heated argument on one of the city's southbound A trains ended in gunshots.
Police say the suspect shot a teenager, reportedly only 15 years old, in the chest.
Authorities said it wasn't clear if the two knew each other.
"Whether this had any gang or crew nexus to nexus to it that is an avenue that will be explored," said Jason Wilcox, Chief, NYPD Transit Bureau.
A Good Samaritan pulled the young man off of the train that was pulling into the city's Far Rockaway - Mott Avenue Station.
Two police officers immediately began to administer first aid, but the teenager died later at a local hospital.
New York police say this is the eighth homicide on the city's transit system this year and the fourth in just the past two weeks.
Authorities say seven of the murders this year have ended in arrests, but passengers on New York's subway system are worried.
"I take the train, and you never know. It could happen to me. It could happen to anyone," Aaliyah Polanco, Far Rockaway Resident.