Let I ⊂ R = K[x 1 , . . . , x n ] be a square-free monomial ideal, q be a prime monomial ideal in R, h be a square-free monomial in R with supp(h) ∩ (supp(q) ∪ supp(I)) = ∅, and L := I ∩ (q, h). In this paper, we first focus on the associated primes of powers of L and explore the normally torsion-freeness of L. We also give an application on a combinatorial result. Next, we study when a square-free monomial ideal is minimally not normally torsion-free. Particularly, we introduce a class of square-free monomial ideals, which are minimally not normally torsion-free.