As crime changed with the internet revolution, New York Police Commissioner William Bratton said at an Internet Week event on Wednesday, police had to respond to the change. Prostitution was moving from the streets to Craigslist, data breaches yielded the potential for large-scale in identity theft and even simple debit card theft at ATMs became a problem.

"Twenty years ago, as police commissioner of New York the first time, I had a flip phone and a beeper," Mr. Bratton said during a conversation with Gerry Byrne, Reisenbach Foundation chairman and vice chairman at Penske Media. "The concept of smartphones didn't exist."

As commissioner for a second time, now serving Mayor Bill de Blasio instead of Mayor Rudy Giuliani, Mr. Bratton said he has focused on tech. He plans to equip police with 35,000 smartphones and 6,000 tablets this year, and a $400 million NYPD budget investment will improve tech, training and facilities, according to Mr. Bratton.

Newer crime prevention methods include data mining, in which police watch for possible terrorist threats by scanning the web for particular keywords. Data mining is important because terrorism prevention depends on both information access and turning that information into actionable intelligence, the commissioner said.

Mr. Bratton even called 2015 the year of tech for his department. All police vehicles will have GPS, and 750 miles of fiber optic cable will be installed in offices to speed up devices. The NYPD will also gain apps for mobile fingerprinting and language translation, vital in a city that speaks many languages and receives visitors from around the globe.

And the NYPD will use ShotSpotter, a sensor system that alerts police to shots fired, Mr. Bratton said. The commissioner said the sensor could alert police to gang-related shots one night, preparing them for possible retaliation.

"By the end of this year, going into 2016, we will be the most technologically advanced police department in the country," Mr. Bratton said.