THE BRONX - Police are searching for the person who fatally shot a teen during a dispute on a train in the Bronx Sunday.

Police said two groups of young men got into an altercation on the 5 train as it traveled northbound between the Dyre Avenue and E. 180th Street stations. A single gunman shot four people in front of other passengers around 2:30 a.m., according to officials.

Rayquan Story, 19, died at the scene; three other teens were wounded. A 19-year-old was treated for a gunshot wound to the abdomen and an 18-year-old was shot in the forearm. Another 18-year-old was shot in the pinky finger.

Authorities believe the gunman slipped off the train; no arrests have been made in the incident.

Story's relatives gathered at the train station while police taped off the crime scene and searched for clues. Family members said they want to know why no cameras were at the station.

A spokesman for the Metropolitan Transportation Authority said the case is being handled by police.

AP wire reports contributed to this story.