NYPD detectives have arrested two teens for fatally shooting an 18-year-old woman in the head as they played with a gun at a NYCHA complex in Hell’s Kitchen last year, police said Friday.

A 16-year-old boy is facing manslaughter, criminally negligent homicide and weapons possession charges for the death of Kimberly Olmos, who was found shot in a stairwell at NYCHA’s Harborview Terrace complex on W. 56th St. near Tenth Ave. in Midtown around 12:45 a.m. on Nov. 2, cops said.

The boy, who was arrested Wednesday, was not named because of his age.

A second teen, 18-year-old Abdel Velazquez, was arrested in December for allegedly stashing the gun that was used in the fatal shooting. He’s facing criminal charges of weapons possession and tampering with evidence.

Velazquez lived in Hell’s Kitchen near where the shooting occurred, cops said.

Police said the 16-year-old suspect was playing with the gun when Olmos was accidentally shot.

Olmos was found alone and mortally wounded in the stairwell. Medics rushed her to Mount Sinai West, where she died a short time later.

Cops reviewing surveillance footage spotted Velazquez leaving the building with a backpack. The front of the building was fenced in and under construction, but cops could see the teen hiding the backpack “underneath a large piece of plywood” near the entrance before jumping over a fence and running off.

Investigators went to the piece of plywood and found both the backpack and a gun inside that was a match to the one used to kill Olmos.

Detectives then used area surveillance cameras to track Velazquez, who was wearing a black sweatshirt with a distinctive red logo on the back, to his building.

Hours after the shooting, the building stairwell was still splattered with blood, including a large pool of it on the second-floor landing.

“It started from the second floor coming down, so, like, three of the steps are littered with blood,” said a man cleaning up the crime scene. “It’s pretty bloody in there.”

A funeral for Olmos was held on Nov. 9.

Kimberly Olmos was fatally shot in a stairwell at the Harborview Terrace complex on W. 56th St. on Nov. 2.

Theodore Parisienne / New York Daily News

Kimberly Olmos was fatally shot in a stairwell at the Harborview Terrace complex on W. 56th St. on Nov. 2. (Theodore Parisienne / New York Daily News)

“She was genuinely the sweetest girl you could ever meet, talk to and be around,” a relative wrote on a GoFundMe post, which raised more than $2,000 for her funeral expenses. “She was a great friend, great daughter and a beautiful soul.”

“She was in high school,” the victim’s father, Richard Olmos, told the Daily News in an exclusive interview in November. “She was going to the Dominican Republic for vacation on Nov. 14. She was really happy about it. She was so happy that she was counting days.”

“Last Wednesday, she wanted some money, and I told her I am going to send her money to go to the Dominican Republic,” her father said. “She was so happy. I am surprised that all this happened.”

The victim’s parents are from the Dominican Republic, but she was born in New York.

The teen lived in the Morris Heights section of the Bronx with her mother.

Olmos confessed that he was “concerned about the people she was hanging out with,” he said.

“We would tell her not to deal with this kind of people, but she is 18 years old. We cannot do much.”

Following an autopsy, the city medical examiner’s office determined she died from a gunshot wound to the head. Her death had been deemed a homicide, an agency spokeswoman said.

The 16-year-old’s arraignment was pending Friday, officials said. A grand jury indicted Velazquez, who is expected to be arraigned on the indictment on Feb. 4, according to court records.

In a statement, Brian Kennedy, Velazquez’s attorney, maintained that his client was not involved in the fatal shooting.

“It has been made clear that the police and the district attorney do not believe that Mr. Velasquez was responsible for the shooting, or that he was an eyewitness to the shooting,” he said.

“The family of the girl who was killed deserves everyone’s thoughts and prayers. Mr. Velasquez offers his most sincere condolences.”