The father of an infant who was killed earlier this month when a stray bullet struck her was the target of the shooter, the police said on Tuesday.

The infant, Kaori Patterson-Moore, was sitting in a stroller near her parents, outside a deli in the Williamsburg neighborhood of Brooklyn on April 1, when two men on a motorbike sped up to the corner of Humboldt and Moore Streets, according to the police.

One of the men, who the police later identified as Amuri Greene, 21, fired shots into a crowd of adults and children, striking the baby and her 2-year-old brother, who was grazed in the back. The men then sped off as the baby’s father, Jamari Patterson, began screaming and picked up his lifeless child, according to witnesses. The two men have been arrested and charged with murder in the death of the 7-month-old girl. Both have pleaded not guilty.

Mr. Greene, who was caught that day, later told the police that he had wanted to shoot Mr. Patterson, a gang rival who he said had shot at him the day before, said Joseph Kenny, the chief of detectives for the New York Police Department.

Chief Kenny said the detectives had not recovered any evidence that Mr. Patterson tried to shoot Mr. Greene the day before his daughter was killed.

“There is no indication that it even took place,” Chief Kenny said.

The two men, Mr. Greene and the driver of the motorbike, Mathew Rodriguez, 18, “went out with purpose” to Williamsburg that day, Chief Kenny said. “They went out there to take a life.”

Both men were arraigned earlier this month on several charges including murder. Mr. Rodriguez fled after the shooting to rural Pennsylvania where he was with family and was caught two days later by the police in Barrett Township, two hours northwest of Williamsburg near the Pocono Mountains.

Just before his arraignment, as he was led to a police vehicle, Mr. Rodriguez wept and insisted he did not know Mr. Greene had planned to shoot at the crowd.

“I promise I didn’t know,” Mr. Rodriguez yelled at reporters. “I didn’t know it was going to happen.”

The two gangs have been targeting each other for years, committing acts of violence to settle grievances that arise out of social media posts, including rap songs that threaten and taunt each other, Chief Kenny said.

The feuds, like many that the police say drive gang violence in the city, are based more on historical tensions over geography, with groups of people shooting at one another because they live in different neighborhoods or housing projects.

“Historically, there would be gang wars over territory for drugs, territory for prostitution, money making, credit card fraud,” Chief Kenny said. The more recent feuds come “down to them simply disrespecting each other during these rap videos,” he added. “It’s geography. It’s development versus development.”

Right after the arrest, Mr. Greene waived his Miranda rights and confessed he was the shooter, Chief Kenny said.

The shooting, during daylight hours on a busy Brooklyn street, stunned city officials and residents of the neighborhood.

A large crowd, including Attorney General Letitia James, Representative Nydia Velazquez and Public Advocate Jumaane Williams, appeared at a vigil earlier this month for the baby.

“My family is broken, I am broken,” said Arlene Poitier, the baby’s great-grandmother. “I don’t have her to sleep with me at night anymore.”

A makeshift memorial had been set up outside the deli, where the sidewalk was festooned with dozens of colorful votive candles, mylar balloons and oversized stuffed animals.

Nestled among the keepsakes was a photo collage of Kaori and two posters that read, “Don’t Shoot. I Want To Grow Up.”

Nate Schweber contributed reporting.