Far from the city’s major Chinese enclaves, a couple left their Bronx apartment on Sunday headed to Chinatown for breakfast on a crisp fall morning. A few blocks to the D train. A short wait on the platform.
Then, without warning, the husband disappeared beneath the screeching downtown train, pushed to his death, apparently by a stranger, just before 8:45 a.m., the police said.
“Push, push!” his stricken wife screamed, according to witnesses, uttering one of the few English words she knew.
An assailant fled up the stairs and out onto the street.
Nothing was stolen, the police said, nor did the smattering of early Sunday straphangers describe a prolonged confrontation between the victim, Wai Kuen Kwok, 61, and his assailant.
Instead, investigators came to believe as of late Sunday, that the attack was the sort that sows fear in many New York City subway riders: a random, purposeful and fatal shove at the platform’s edge by a stranger.
Before Sunday’s death in the Bronx, 49 people had been struck and killed by subway trains this year, according to a spokesman for the Metropolitan Transportation Authority, a number that includes suicides as well as accidental falls. But Mr. Kwok’s killing was the first time since late 2012 that a rider was deliberately shoved to his death by another.
The police released surveillance video of a man described by witnesses as the assailant, who remained at large as of Sunday evening. The video shows the man walking from the station exit, riding a local bus, the BX35, and smoking a cigarette on the sidewalk. Detectives believed he may live in the vicinity of the 167th Street station, where the attack took place.
Even without surveillance video of the push, the police said other evidence made clear that Mr. Kwok, who last worked for a kitchen supply company, had not fallen on the tracks by accident or jumped into the path of the train. The motorman on the southbound D train told detectives that the man’s body suddenly flew in front of the train, the police said.
Alfredo Brown, 36, who was in the station on his way to church on Sunday morning, said he heard “a commotion,” though other witnesses told the police that there did not appear to be any confrontation.
The victim’s wife, 59, who was not injured, was taken to Bronx-Lebanon Hospital Center for observation. By Sunday afternoon, detectives at the 44th Precinct station house, with the assistance of family members, had interviewed the woman, who speaks Cantonese.
“Please tell the world he is a fine, regular family man,” said his son, Gary Kwok, 29, a doctoral student at Adelphi University who lives with his parents in their Bronx apartment.
The last time a subway rider died after being pushed onto the tracks was December 2012, when a woman shoved a man into the path of a 7 train along an elevated stretch in Queens. The woman, Erika Menendez, was charged with murder as a hate crime in the death of the man, an Indian immigrant.
Before Sunday’s attack, Mr. Kwok and his wife had been on their way to Chinatown, a weekend ritual for the couple.
Inside their third-floor apartment, relatives huddled around Mr. Kwok’s wife. Neighbors described the family as friendly, generous and nearly inseparable. “Whenever they go out they are always together and they always come back together,” said Dely Ramos, 64, a longtime resident of the building.
Jaime Wu, 21, who lives in a downstairs apartment with her mother, said Mr. Kwok’s wife watched over her when she started riding the train in middle school. “She would wake me up and make sure I didn’t miss my stop,” Ms. Wu said.
Ms. Wu’s mother, Yan Lian Liang, would often ride to Chinatown with Mr. Kwok and his wife.
However on Sunday, Ms. Liang, a home health aide, had been returning from work when her train stopped halfway into the 167th Street station. She heard an announcement, but understood little of the English. As she climbed the stairs out of the station with the other passengers, a woman could be heard screaming and sobbing on the platform.
“I heard screams but at the time I didn’t know what was happening,” Ms. Liang said, speaking in Cantonese. “Later, when I got home, I found out.”