Velocity of galaxies with respect to the cluster mean velocity vs. the projected distance from the group centre D_gr for group Gr12 galaxies. Filled red symbols show galaxies with old stellar populations (D_n(4000)≥1.55), and empty blue symbols denote galaxies with young stellar populations (D_n(4000)< 1.55). Green triangles indicate recently quenched galaxies, and orange stars denote AGNs. Red star shows the location of the BGG.