The widow of a New York Police Department (NYPD) officer who was murdered in 2014 has given birth to his daughter — almost three years later.

Wenjian Liu, 32, and partner Rafael Ramos, 40, were shot in 2014 as they sat in their patrol car in Brooklyn.

Both men later died in hospital, where Liu’s widow, Pei Xia “Sanny” Chen, was asked if she would like to preserve her husband’s sperm so she could someday have his child.

On Tuesday, more than two-and-a-half years later, Ms Chen gave birth to their baby, a girl named Angelina, at Weill Cornell Hospital.

Liu’s parents, Wei Tang Liu and Xiu Yan Li, were also there to celebrate the birth of their granddaughter.

Wei Tang Liu and Xiu Yan Li with their newborn granddaughter, Angelina. Photo: NYPD

Ms Chen never doubted she would have a daughter, saying the night after her husband passed away, she had a dream in which he handed her a baby girl.

“I got pregnant through the [in-vitro fertilisation] procedure and I told my friend, ‘It’s going to be a baby girl’. My friend said, ‘No, you haven’t even checked the sonograms’, but I was right,” she said.

Liu and Ms Chen had been married for just three months before the murder, and were trying for a child at the time.

The shooting occurred hours after the gunman, 28-year-old Ismaaiyl Abdula Brinsley, warned on social media he planned an attack in retribution for recent US police killings of unarmed black men.

Brinsley travelled from Baltimore — where police said he had shot and wounded his girlfriend — to New York, and during the day posted on Instagram he would be “putting wings on pigs today”, using an anti-police slur.

After shooting Liu and Ramos, Brinsley fled to a nearby subway station where he shot himself and died.

At Liu’s funeral, Ms Chen said: “Wenjian is my hero. Wenjian will always live in our hearts, my heart. We love you, I love you, forever love you.”