Biscuit ang tea? You need to take more water with it chap.
Murders, along with most other crime, are very rare in Guernsey, the last one that I can recall was in 2007. Allegedly if the Guernsey police recruit any UK officers they have to be 're-educated' into Guernsey life. Part of the re-education is that minor offences are worth pursuing as their day isn't filled with more serious crimes.
Obviously not everything is rosy, we have our share of Richard Craniums, one of the benefits of a small island is that they are well known to the police so they generally know who has done what.