[W. mentioned Sawney Bean at the Jul 2000 ADG get-together, and I looked him up on the Internet.]

Sawney Bean dates from the time of Scotland's King James VI (later King James I of England). Supposedly, he led his incestuous descendants in a secretive robbers' band. Over the years, they are estimated to have killed and eaten about 1000 people.
"Sawney" is a common Scots nickname, the diminutive of "Alexander."

[Postscript 2012/03: the current historical consensus is that he was a legend.]

Cross-cultural note:

A Russian equivalent to Sawney Bean was the serf-owner Dar'ya Nikolaevna Saltykova (1730-1801), commonly known under a nickname of infamy "Saltychikha". A government inquiry determined that she had tortured and murdered at least 38 serfs, and probably 26 more. She was denounced in 1762, and sentenced to death in 1768, but the death sentence was commuted to lifelong internment in a nunnery. Her nickname became a byword for cruelty