It was announced yesterday by the Public Prosecutor's Office in Torre Annunziata (nearest one to Pompeii) that nine people are under investigation by the carabinieri for "disastro colposo" which can loosely be translated as "negligence" in English and is a fairly serious crime. This is specifically connected to the collapses of the Schola Armaturarum and the House of the Moralist.
The investigations are focusing on those involved in the management of the site before the Special Commissioner was appointed (i.e. before 2008), and include former Superintendent Guzzo, site director Antonio Varone and other Soprintendenza staff.
Technical consultants will be called in to identify the causes of the collapse as part of the investigation.
News coverage in Italy is surprisingly brief, for example this article, but I imagine that the issue will continue to attract public interest as developments occur.