Dissociative electron capture accompanied by target ionization (DECI) was studied for collisions of 20 keV H2+ with Ar. A three-dimensional fragment imaging technique in combination with a recoil-ion time-of-flight method was used to measure the kinetic-energy release and the dissociation angle of the H–H fragment pair arising from the DECI process. We observed that the distribution of the dissociation angle is strongly anisotropic. A three-body simulation suggests that collisions between the individual fragments and the target significantly influence the two-body dissociation of the H–H pair at impact parameters where the DECI process occurs.