Killed on 22 august 1965 in a lovers' lane near a lake in Grossenbaum-Duisburg.
25 years old
Stabbed in the heart twice, he died immediately. Kroll got sight of Rita A., making love to Schmitz in their Volkswagen. He punched a knife through a tire of the car, whereupon Schmitz got out to see what happened, Kroll stabbed him in the chest, turning to the girl. The girl watched in despair her boyfriend collapse and jumped in the driver's seat, disregarding the flat tire, hooted the horn like frantic and drove straight off onto Kroll, who barely managed to turn his heels and make his escape. While Schmitz bled to death in the arms of his girlfriend, the area was swarmed with alarmed drivers but no trace of the mysterious attacker was found.
Kroll's only male victim.