It was a fight over $1 dollar that led a young thug to kill his grandmother in her Wagner Houses apartment last month, officials revealed today.

Larry Davis, 22, confessed to cops that he had asked his grandmother Cora, 76, for $175, then became “frustrated” and shoved her when she only gave him one buck, officials said.

The grandmother fell backward onto her kitchen floor, fracturing her neck, assistant district attorney Robert Ferrari said in Manhattan Criminal Court.

The slaying garnered headlines after cops said that Davis stuck the woman’s corpse into her bedroom closet, then embarked on a two-day tryst with a hooker just six feet away — on the dead woman’s bed.

Davis is being held without bail pending his next court date, June 1.