Cold-blooded home invaders in the Bronx threatened to shoot a boy and pistol-whipped a grandmother before making off with a safe containing $40,000, police said.

The chilling home invasion unfolded around 8 a.m. Wednesday inside of an apartment in the vicinity of Gates Place and West Gun Hill Road, authorities said.

The three robbers waited outside the apartment of a 30-year-old woman until the door was eventually opened, cops said. The terrifying trio then stormed the residence and pointed a gun at the woman’s 5-year-old son and threatened to shoot him unless she gave them money, police said.

The armed bandits pistol-whipped the victim’s 58-year-old mother and forced the 30-year-old woman into a back bedroom where there was a safe stuffed with $40,000 cash, authorities said. Police would not speculate on the cash.

The trio stole the safe, with two of the three robbers speeding off with it in a gray sedan; the third thief drove off in a dark blue SUV, police said.

The 30-year-old and her 5-year-old son were not injured. The 58-year-old woman declined medical attention, cops said.

One of the robbers was last seen wearing a black face mask, a gray hooded sweatshirt with a Nike logo on the front, dark colored pants and white sneakers. A second suspect, was last spotted wearing a black face mask, black hooded sweatshirt, black pants, black sneakers and white gloves, cops said.

Those two made off with the safe in the gray sedan, authorities said. The third suspect was last seen wearing a black face mask, a black hooded sweatshirt, blue jeans, black sneakers and white gloves, the NYPD said.

Anyone with information in regard to this incident is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477).