It means "John Lennon is dead". Alternatively, 'john' can be substituted for any other name to create the same effect

Originating from 4chan, "john is kill" was the assumed 'title' of a thread about the assassination of John Lennon seemingly typed out by someone with very little English skills, to comedic effect. The OP was asking people where they were and what they were doing when they heard about John's assassination. Now the thread is sometimes recreated using the same picture of John and using the same format, although sometimes Heath Ledger is used instead (or heat ledger, as it is typed out in homage to the original OPs poor English)
"apology for poor english

when were you when john lenin dies?

i was sat at home eating smegma butter when pjotr ring

'john is kill'

'no'"
by OLPZach January 9, 2014
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