The NYPD has arrested 25-year-old Mark Smith in connection to the fatal stabbing of an 18-year-old while riding the D train in Brooklyn.

Police responded to a call on April 6 at 11:30 p.m. for a male stabbed on a northbound D train as it entered the 4th Avenue and Pacific Street station. Officers found 18-year-old Isaiah Collazo with a stab wound to the abdomen. The victim was transported to New York-Presbyterian Brooklyn Methodist Hospital, where he died due to his injuries.

Smith was walked out of the 84th Precinct in handcuffs and is facing multiple charges including manslaughter, assault, and two counts of criminal possession of a weapon. When asked to speak while walking out of the precinct, Smith claimed he was innocent and only protecting himself.