Unless they had instructions from the Southern Government, I would suggest the Confederates were as responsible for them as the Union was responsible for John Brown.
Also the reports would seem to indicate that these people attacking the Massachusetts troops were all Marylanders, which If I recall correctly was a Union state. Dissidents, it would appear.
No, the first officially sanctioned bloodshed would still appear to be the attempted invasion of Virginia.
If you're not a member of the Trial Lawyers Association, I think you missed your calling in life with that rationalization.
But the jury here isn't impressed. ;~))