Some cases of sexual serial killing exemplify anger directed at an ex-wife/partner, which gets transferred to other women. These involve (1) displaced aggression and (2) collective guilt of women as a whole, or particular types of women, such as sex workers. Faryion Wardrip exemplifies anger directed towards his ex-wife, and he reported seeing her face as he was killing. The killings appeared to be unplanned. Russian police officer Mikhail Popkov discovered his wife had committed adultery. Dividing women into saints and sinners, his discovery triggered a campaign of raping and then killing those he considered to be immoral. He would offer women lifts in his car and invite them for a drink. If they gave an answer of the kind 'Sorry but I must get home', they were spared, even escorted to their front doors. If they answered 'yes', this was a death sentence - an example of ‘mission killing’.