Green’s Dictionary of Slang

to strike or beat to death with a poker.

[1770		in Cases Argued and Adjudged in the Court of King's Bench (1756-72) (1808) V 2647: In the year of our Lord of 1769 [...] the said Matthew Kennedy , with a certain iron poker of the value of six-pence, which he the said Matthew Kennedy had in his right hand, then and there [...] feloniously wilfully and of their malice aforethought did strike [...] the said john Bigby [etc.]] .
1824		J. Wight Mornings at Bow Street 111: What does Mykle do, but seize the poker, and threaten to ‘Kennedy him*’ if he dared to interfere with his private amusements [...] [note] *Kennedy — St Giles for the poker, from a man of that name being killed with a poker, or a man of that name killing another with that instrument.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1895		(ref. to 1831) Truth (Sydney) 17 Feb. 3/8: On Saturday 28th May (1831) a convict [...] only escaped a lashing through the humanity of his master. [He] was ‘charged with threatening to Kennedy (beat with a poker) one of the constables.