Once again, an aspiring altar boy who was only helping blind orphaned baby seals cross the street, accidentally tripped off the curb into a carjacking, or something like that:

A retired NYPD cop shot and killed an 18-year-old gunman who tried to carjack him in Brooklyn early Tuesday, police sources said.

The teen, Manuel Ocampo, and an accomplice allegedly tried to hold up retired Police Officer Derek Bishop as he sat in a Mercedes 430 at Georgia and Linden Aves. in East New York about 3:15 a.m.

Bishop was working security at a nearby recycling plant when Ocampo and his 18-year-old cousin approached the car, pointed a gun at him and demanded his money and wheels.

At first, Bishop gave the pair some money, but the duo demanded more, police sources said.

The cousin, Rashawn Thompson, moved to the passenger side door, police sources said. Ocampo stayed on the driver’s side.

Bishop got out of the car, drew his weapon and opened fire, hitting Ocampo in the chest and head, officials said.

The attempted carjacking was  was very out of character for Ocampo, according to his brother.

Ocampo, of Coney Island, had one arrest on his record, for selling marijuana, police said. He also had pot on him when he was shot, according to cops.

Ocampo’s family said the teen had one more year left at Liberation Diploma Plus High School on Coney Island and worked as an intern looking after kids at the Carey Gardens Child Care Center on W. 23rd St., Brooklyn.

“He was only 18,” his sobbing brother, Christopher Ocampo, told the Daily News. “He wasn’t no thief.”

Evidence to the contrary suggests otherwise.