Richard Rojas was charged with one count of second-degree murder, 20 counts of attempted murder, and five counts of aggravated vehicular homicide.
The incident began as Rojas was driving south on Seventh Avenue through Times Square, police said.
Richard Rojas enlisted in the Navy in 2011.
O'Neill, at Thursday's news conference, said, "Preliminary investigation reveals that Rojas has two arrests ... for DWI".
One neighbor says Rojas is a "good person" and he doesn't know what happened to him. Police identified her as 18 year old Alyssa Elsman of Portage, Michigan. The New York Times reports that he asked for a lawyer, but information about his attorney was unavailable Friday morning.
"It appears to be intentional in the sense that he was troubled and lashing out", New York City Mayor Bill de Blasio said in a radio station interview on Friday.More news: California Highway Patrol issues AMBER Alert for missing one year-old
Rojas spent his final months in the Navy at NAS Jax before being discharged in 2014 as the result of a special court martial, a Navy official said.
Officers have interviewed Mr Rojas' mother, with whom he lived in the Bronx, and are obtaining a search warrant for their apartment. They don't indicate why.
Protective bollards - short, sturdy posts to prevent vehicles from driving onto sidewalks - were installed late last year, just in time for the New Year's Eve celebration that regularly brings a million or more people to Times Square to watch the famous Waterford crystal ball drop at the stroke of midnight.
Richard Rojas, a 26-year-old NY native, allegedly ploughed his red Honda sedan through the popular tourist destination on a sunny Thursday morning. The circumstances surrounding the court-martial were not immediately available.
NYPD sources say the Bronx native told officials he experienced hallucinations, and later "alluded to suicide by cop" and "the end of days".
Elsman graduated from Portage Central High School in 2016.More news: Trump Tells Russians That Comey Firing Relieved Pressure
During his arrest, Rojas allegedly told police: "You were supposed to shoot me!"
The young woman is remembered by her principal as thoughtful, compassionate and bright.
Law enforcement officials say a man accused of steering his vehicle onto one of the busiest sidewalks in the US and mowing down pedestrians for three blocks told police he was "hearing voices".
"People just got stunned", said Bruno Carvalho, a student at SUNY Albany. He barreled straight up the sidewalk, knocking down some pedestrians as others ran in terror, before he crashed his auto into protective barriers.
"I was in shock, I was screaming", witness Kristen Boyce said.
President Donald Trump has been made aware of the situation and will continue to receive updates, according to White House press secretary Sean Spicer.More news: Real Madrid beat Atletico to advance to 2017 UEFA Champions League final
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