The grief-stricken father of the young woman fatally mowed down by a maniac driver speeding down a Times Square sidewalk said Friday, “My heart died in New York yesterday.’’

Thomas Elsman drove to the city from his Michigan home with his son Thursday night after hearing the awful news about 18-year-old Alyssa.

He told WNYW/Fox 5, “There’s no words. I want to scream. My first-born daughter is gone.’’

Alyssa, her 13-year-old sister, Ava, and their mom were visiting New York when Richard Rojas struck.

At one point Friday, Elsman went to the Midtown South station house where Rojas was being held, and threatened to kill him, law-enforcement sources told The Post. Elsman was taken to Bellevue Hospital to be calmed down.

Meanwhile, sources said Ava was more seriously injured than had been reported. She suffered a fractured pelvis and collapsed lung in addition to a broken leg.

Ava was told that her sister died in the tragedy, their father said.

Elsman was outraged when he learned more about Rojas.

“If it was an accident, I would forgive,” he said in the interview.

“The fact that I found out he was on drugs, and then also today in court said, ‘I wanted to kill everyone,’ and he wanted to go suicide-by-cop, that’s intent,” he said.

“He knew what he was doing, and I don’t care what happens to him.”