Yeah, I think it is more phonetic shorthand than any kind of cypher. Unfortunately, it's a long shot that we'll be able to get any insight into it without knowing more about the victim's personal characteristics or habits.
Here are some other links to save you some searching:
http://www.websleuths.com/forums/showthread.php?t=131822
http://nl.newsbank.com/nl-search/we/Archives?p_product=SL...
http://nl.newsbank.com/nl-search/we/Archives?p_product=SL...