Green’s Dictionary of Slang

Killsome n.

(W.I.) Kingston, Jamaica.

[UK]N. Farki Countryman Karl Black 13: The country parts bad but not half as bad as the city of Killsome.
[WI]L. Goodison Baby Mother and King of Swords 23: Country people called Kingston, ‘Killsome’, and it was a place that had killed some people in its time.