Garudapurana 1.65.116

1.65.116

smite kūpe gaṇḍayośca sā dhruvaṃ vyabhicāriṇī /
pralambinī lalāṭe tu devaraṃ hanti cāṅganā //

and dimples appear on her cheeks when she smiles, she is certainly adulterous. / A hanging fold of skin on the forehead, that woman kills her husband's younger brother;