Killed on 12 july 1969 on the Hardenbergufer of the Baldeneysee in Essen-Werden.
61-year-old pensioner.
Kroll went on a little trip from Duisburg to Essen by train, then took a bus to Werden for a stroll on the banks of the Baldeney-lake. There he encountered Hettgen, and got a 'tickling feeling all over'. He started talking to her but she declined, he hit her, they fell into some bushes where he raped and throttled her.
She was found the next day.