"Serial rapist" means "has more than one victim", not "rapes strangers". It is entirely possible for one person to rape ten people who know and trust them, and

"Serial rapist" means "has more than one victim", not "rapes strangers". It is entirely possible for one person to rape ten people who know and trust them, and not at all surprising that anyone sleazy enough to do this would likely be a repeat offender especially when there's such a high probability of getting away with it. The numbers are quite staggering though: "A rapist rapes on average seven to 11 times before they're caught. ... Of our set of 817 ... over 50 of them have 10 to 15 hits apiece."