<p>A 21-year-old Brooklyn man was arrested in the fatal stabbings of two people on New York City subway trains, police said Sunday.</p>.<p>Rigoberto Lopez was taken into custody Saturday night and was formally arrested Sunday on charges of murder and attempted murder, police said.</p>.<p>One of the victims was discovered dead on a train in Queens late Friday with several stab wounds to his neck and torso, police said. Two hours later, a 44-year-old woman was found stabbed to death in a subway car in upper Manhattan.</p>.<p>Two nonfatal attacks — one involving a 67-year-old man and the other involving a 43-year-old man — also occurred in upper Manhattan. Authorities believe all four victims were homeless.</p>.<p>Police said they believe Lopez may have committed all of the attacks. It wasn't clear if he had an attorney who could speak for him.</p>.<p>Police leaders said they would deploy an additional 500 officers into the subway system to guard against future assaults. "To the victims, to the victims' families, we are 100% committed to getting justice … to bring closure to the families of this terrible incident," NYPD Commissioner Dermot Shea said Saturday.</p>
<p>A 21-year-old Brooklyn man was arrested in the fatal stabbings of two people on New York City subway trains, police said Sunday.</p>.<p>Rigoberto Lopez was taken into custody Saturday night and was formally arrested Sunday on charges of murder and attempted murder, police said.</p>.<p>One of the victims was discovered dead on a train in Queens late Friday with several stab wounds to his neck and torso, police said. Two hours later, a 44-year-old woman was found stabbed to death in a subway car in upper Manhattan.</p>.<p>Two nonfatal attacks — one involving a 67-year-old man and the other involving a 43-year-old man — also occurred in upper Manhattan. Authorities believe all four victims were homeless.</p>.<p>Police said they believe Lopez may have committed all of the attacks. It wasn't clear if he had an attorney who could speak for him.</p>.<p>Police leaders said they would deploy an additional 500 officers into the subway system to guard against future assaults. "To the victims, to the victims' families, we are 100% committed to getting justice … to bring closure to the families of this terrible incident," NYPD Commissioner Dermot Shea said Saturday.</p>