By mid-July, the 4th Panzer Group seized the Luga bridgehead and had plans to advance on Leningrad. The staff and detachments 2 and 3 of "Einsatzgruppe A", one of the mobile killing squads following the Wehrmacht into the occupied Soviet Union, were brought up to the Luga district with assistance from the army. "The movement of "Einsatzgruppe A"—which the army intended to use in Leningrad—was effected in agreement with Panzer Group 4 and at their express wish", noted Franz Walter Stahlecker, the commander of "Einsatzgruppe A". Stahlecker described army co-operation as "generally very good" and "in certain cases, as for example, with Panzer Group 4 under the command of General Hoepner, extremely close, one might say even warm".