A 13-year-old boy was fatally stabbed on an MTA bus Friday on Staten Island.

The incident took place near the Hylan Boulevard and Littlefield Avenue in Eltingville around 2:30 p.m, per CBS News. Authorities have taken a 14-year-old boy into police custody in connection with the incident. Witnesses on the bus claimed the 13-year-old victim and the 14-year-old suspect engaged in a heated argument, allegedly escalating into a violent confrontation.

“Witnesses state there’s an argument on a bus. A knife is produced, and gang signs were being shown back and forth,” NYPD Chief of Patrol John Chell said in a statement. The 14-year-old allegedly stabbed the victim in the chest during the confrontation.