We Stumbled Upon a Voodoo Ritual at Soop Cemetery

It was one year ago this week.
Soop Cemetery in the small town of Belleville, Michigan is said to be one of the state's most haunted locations... something we knew firsthand, having been to the cemetery a few times before.
On our first visit, with the Michigan State University Paranormal Society, an investigator fainted, having heard something behind her. When we returned on our own, we captured a potential shadow figure on camera, after hearing a loud hiss that startled us.
Both experiences, the fainting and the shadow figure, seemed to come from the direction of one grave: Elizabeth Soop.
In fact, a majority of the cemetery's legends center around Elizabeth; she was a known witch, and in death, still roams her family's namesake cemetery. Interestingly, the most common reports here are of shadow figures and strange disembodied voices.
The reason for our third visit, one year ago this week, was twofold: to test out new equipment at a location known to be active, and to conduct a concentrated investigation only of Elizabeth Soop's grave, to determine once and for all if she truly is behind the activity.
When we approached Elizabeth's grave this time, though, there was something different. Leaves were covering the ground everywhere except atop her grave. In place of leaves were a circle of coins, and other small "offerings." It seemed a little strange, but what made us question what we walked into was the discovery of a large bone in the center of her grave.
A demonologist later told us that it was a clear voodoo hoodoo ritual that we discovered, one that was likely done just an hour or two before we found it (we knew this because it rained in the morning, but the dollar bills were all dry).
We decided to do an experiment: we put the bone on our SB-7 Spirit Box, which was one for about 40 minutes prior, and not one voice was heard. As soon as we placed the bone on it, though, a deep man's voice instantly boomed "PRAY!"
When asked where the bone came from, the same voice came through again, clearly saying "from a dead cow."
It did appear to be a cow bone.
These voices, combined with unexplained and intelligent EMF spikes, left us with more questions than answers.
Is Elizabeth Soop behind the activity? Or, if people truly are doing rituals atop her grave, could they be the ones stirring up the already present activity?