There's a new Case Report in the Journal of Analytical Toxicology
The victim was a 30 year old male, found in a stairwell in a "critical state". Emergency response was ineffectual and the individual died at the scene. The toxicology testing found his blood and vitreous humour positive for mephedrone (5.5 and 7.1 ug/mL, respectively). There was no alcohol in the individual, no positives on "routine screening analysis" nor any sign of amphetamine, methamphetamine or MDMA. The 2C-B compound initially suspected by police (based on some field assay, looks like) was not confirmed in the powder in his possession nor in tissue samples.
That's it, short and sweet. The mephedrone (aka 4-methylmethcathinone) killed him.
Additional reading on the substituted cathinone designer drugs of abuse can be found in my archive.
Related reading on MDMA-induced fatality can be found in the MDMA Archive.