This is the lethal “ghost gun” cops believe was the murder weapon in Friday’s stray-bullet shooting death of a Bronx 16-year-old girl, according to law enforcement sources.

The black Polymer 80 9 mm handgun was recovered by cops after 17-year-old Jeremiah Ryan allegedly tossed it out of his fourth-floor apartment in the Bronx in the aftermath of Friday’s fatal shooting, police said.

Ryan was arguing with about four others at around 1:45 p.m. when one person in the group made a motion as if he was going for a weapon — prompting the teen to pull his gun and start shooting, a witness told The Post.

Straight-A student Angellyh Yambo was walking home from University Prep Charter High School about a block away when cops said Ryan fired off six rounds, hitting her in the back.

Two other teens who were also shot, one 16 and one 17, are expected to survive. One remained hospitalized Sunday and the other has been released.

Ryan fled and ran home to East 161st Street, where police nabbed him after they said he hurled the unloaded gun out of the window inside a black plastic bag. A source said Sunday that the gun was mixed in with trash inside a garbage bag.

Ghost guns are untraceable weapons that can be assembled from parts purchased online.

Ryan was arraigned Saturday on charges including murder and attempted murder, and ordered held without bail pending a return court appearance on Monday.

Police said he has no prior criminal record, but sources said he has been posting photos of guns online since he was 12, and ran with a Bronx stick-up crew for years.

Forensics tests on the ghost gun have not yet been completed, multiple law enforcement sources said, but detectives believe it was the one that killed Yambo.

Services for the slain teen are to be held at Williams Funeral Home in Kingsbridge from 2 p.m. to 7 p.m. Tuesday, her cousin, Alondra Cruz, told The Post Sunday.

There will be a private viewing for relatives on Wednesday morning with burial at Woodlawn Cemetery in the afternoon.

“She’s like a daughter,” Cruz said. “I took care of her since she was 6 months old. She was a good little girl. A little princess.”

Cruz also called out Mayor Eric Adams and the NYPD for the surge in street violence in the Big Apple.

“The mayor and the police need to stop the violence,” she said. “She didn’t deserve that. Please save our children. Every day it’s someone killing someone.”

A GoFundMe launched by one of the girl’s aunts to raise funds for the funeral had reached $20,055 Sunday, surpassing its goal of $10,000.

Additional reporting by Joe Marino