The NYPD has been stepping up patrols underground amid several high-profile crimes in the subway system, including two recent killings in the Bronx, the agency’s transit chief says. 

NYPD Chief of Transit Michael Kemper joined NY1 anchor Dean Meminger Sunday to provide an update on one of the incidents — Friday's killing on a D train in the Bronx. 

Police said 45-year-old William Alvarez was killed during a fight on board the train. 

The NYPD initially said it wasn’t clear whether Alvarez had been shot or stabbed, but Kemper on Sunday said the city’s medical examiner determined Alvarez died “by gunshot.”

Earlier this month, meanwhile, one person died and five others were hurt in a shooting at a subway station in Mount Eden, police said. 

Kemper on Sunday said police have identified three suspects wanted in connection with Friday’s homicide. The suspects were all caught on camera on the train, which he said has been unusual.

"It's unusual now, it's going to be usual moving forward. And again, we talk about the value of the video system in the New York City subway system. It's thousands of videos throughout the subway system,” he said. “People think they're only on the platforms and mezzanines and by the turnstile areas. The MTA has now been installing them on trains."

Kemper said the MTA wants every train car outfitted with surveillance cameras by the end of the year.

(Spectrum News NY1)

Overall crime was up by more than 45% in the subway system during the month of January, according to Kemper. He said this was largely due to grand larcenies, including pickpocketing incidents and property thefts.

City Hall and NYPD Commissioner Edward Caban have “made significant investments into public safety, cops into the subway system starting, really starting the first week of February, where each day there’s upwards of 1,000 additional cops assigned to patrol the subway system,” Kemper said. 

From Feb. 1 to Feb. 24, overall crime was down nearly 18%, according to Kemper.

“So January spiked, investments made, cops redeployed into the subway system in large numbers, and here we are, and I’m very, very confident that moving forward, we’ll stabilize and we’ll have a reduction,” he said. 

Kemper said he is frequently asked what police officers are doing while they are riding trains and patrolling the subway system.

"Arrests are up dramatically this year. All areas of enforcement are up. Summonses are up for quality-of-life offenses, fare evasion, gun arrests are up, knife arrests are up,” he said. “So if anyone’s asking what our cops are doing, they’re out there working hard.”

Asked if officers in the subway system are working longer hours to support the increased presence, Kemper said all 12 districts in the transit bureau are working 10- to 12-hour tours.

"The additional upwards of 1,000-plus cops a day are, a lot of overtime helps us get to that,” he said.