New York — The 21-year-old man accused of opening fire from the back of a scooter in a botched drive-by shooting in East Williamsburg confessed to police that he was deliberately targeting the infant’s father — but instead struck the 7-month-old girl in the head, killing her instantly and wounding her toddler brother, according to court documents and prosecutors.

Amuri Greene told detectives he had been shooting at his “intended target,” Jamari Patterson, the father of Kaori Patterson-Moore, when he unleashed the gunfire last week near the intersection of Humboldt Street and Moore Street, a criminal complaint filed in Brooklyn Criminal Court revealed.

The confession has sent a wave of horror through the community. What Greene described to investigators — calmly recounting how he missed his mark and instead cut down a baby who had just begun saying her first words — has left even seasoned detectives and prosecutors visibly shaken.

Kaori, a bright-eyed 7-month-old who had only recently started uttering “mama,” was sitting in a double stroller with her 2-year-old brother when the scooter pulled alongside the family. The bullet tore through the infant’s head and grazed her older brother before the pair were rushed to Woodhull Hospital. Despite desperate efforts by medical staff, Kaori could not be saved.

In court Friday night during Greene’s arraignment, Assistant District Attorney Jordan Rossman laid out the devastating sequence: “The defendant missed his target, but shot two of the target’s children — fatally shooting a 7-month-old baby in the head and wounding the baby’s 2-year-old brother.”

The bullet’s path was mercilessly precise in its tragedy: it passed through Kaori’s head and continued into the stroller, clipping her brother.

Greene fled the scene with his alleged getaway driver, Matthew Rodriguez. The pair crashed their moped into a nearby car moments later. Greene was thrown from the scooter, breaking his leg in the fall. He was taken to a hospital, where police arrested him. Rodriguez evaded capture for several days before being apprehended in Pennsylvania; he is expected to be extradited to New York shortly.

Law enforcement officials believe the heartbreaking crime may have stemmed from a senseless, long-running gang feud between rival housing projects. Patterson, the young father, has documented associations with members of the Bushwick Houses-based gang known as Money Over Everything (MOE), which has been engaged in a social media-fueled conflict with a crew from the Marcy Houses, according to NYPD Chief of Detectives Joe Kenny.

“He is not in our criminal group database as an MOE gang member,” Kenny noted, “but based on the geography and where he was at that time, we’re looking into that aspect.”

Yet Kaori’s grief-stricken mother, Lianna Moore, fiercely rejected the idea that her fiancé was the intended target. Speaking to the Daily News, she insisted, “That’s not what it was. Everybody keeps saying that they came out to target my fiancé, but he had nothing to do with it.”

Patterson himself has been devastated. In a letter released to the media at a weekend vigil, the young father poured out his pain and his determination to change. “I miss her so much. I want my baby back,” he wrote. He described how Kaori’s birth had motivated him to turn his life around: “I made sure her and her mom and her brother all stayed with me and vowed I changed my life for them through music. The life I live, even getting different jobs to stay away from negativity, I begin to change things up. Which is facts.”

Greene was held without bail on charges of murder, attempted murder, and assault. He is scheduled to appear in court again on Tuesday.

The case has gripped Brooklyn, shining a harsh light on the random brutality of street violence that can claim the youngest and most innocent victims in a single, split-second act of revenge. For a family simply out for an evening stroll, the nightmare began and ended in the space of a few heartbeats — leaving behind a city mourning a baby who never had the chance to say more than “mama.”