From MOD web site
Following an initial investigation by the Board of Inquiry, the Convening Authority has decided that the Board of Inquiry should be suspended at this stage pending further investigation by the North Yorkshire civilian police authorities, which we will fully support.
No mention of criminal activities, but cant imagine why they would be investigating unless there was a suspicion of something untoward, but as for "a source close to the enquiry" I think it means "I don't know anything so I'll just make it up"