Bundy. He attacked four, killing two and leaving two grievously injured. He also sexually assaulted the two he killed, one by ripping her underwear off so viciously he gave her friction burns, the other with an object rape. The sorority house was almost pitch dark, and he'd never been inside it before. He improvised a weapon from an oak branch from a firewood pile, and also strangled one victim with a stocking. He left a bitemark on a victim, but other than that, no footmarks, no screams from victims or housemates, no fingerprints, and a tighter timeframe. He was in and out in less time, and with far more witnesses in earshot than at King Road. Oh, and he was probably also a bit drunk, given how late this was in Bundy's run and how his alcohol intake stepped up as he decompensated towards the end. It also wasn't the end of his night, he went to a nearby apartment and grievously assaulted another victim after he left Chi Omega.
I'm not saying the two killers - Bundy and the killer of the students at King Road - had the same motivations, skill levels, or fantasy leading up to their respective crimes, but because Bundy did it, we know it theoretically is possible that King Road was done alone, in the dark, possibly under the influence, without the household being awoken or full of screaming, without a prior knowledge of the home, and in well under 20mins.
All the relevant information on Bundy's attack on Chi Omega is available in books, on tv shows, and for free on wikipedia.
Ted Bundy - Wikipedia
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