Personal?
This whole affair is far too personal when someone posts something about having anyone else's personal information. Any personal info is anything but hard to get in this day and age. No mystery there. If you live in Indiana and want to challenge someone in Michigan you certainly don't have a long drive to do so personally rather than making an online spectacle of it.
That said, I would be glad as a neighbor of any dowsers in Indiana to recover any treasure here in the Elgin area, with video support of said recoveries, and give the lion's share to that dowser(s).
In particular I am talking about more one or more safe(s) in the Fox River between South Elgin and Dundee, Illinois. One safe lost in a flood, the other tossed in by bad guys and presumably unopened.
Furthermore, the sight where Secret Service Founder James Pinkerton (of the Pinkerton Agency) confronted the counterfieter's that propelled him into public service might also prove interesting. The story is most of the works of the counterfeiters were destroyed and controversy remains on the exact location. It was either an island in the river or the location of a civil war training camp and cavalry outpost.
Another site of possible interest, an island downstream that Al Capone stayed on. His outfit owned a place called the Hideaway which is now a nice diner on the river. This was a remote sight then and is still hard to find for outsiders unless they are on the river. Now did Al Capone actually get crazy and toss gold coins and silver dollars in the river there or not? Just local legend unproven, but the water there is wading depth.
There is also a grave of two unknown soldiers from Winfield Scott's 1832 pursuit of Blackhawk across the river there. That is where they crossed the Fox River in pursuit. Of course Blackhawk would not have come that way, the Pottawatomies would have had his scalp.
At almost the same point, a Cent Ill bridge crosses the river. In October 1894 several miles west a train robbery took place near Water Station Q, just east of Elburn. The mail car was blown to bits ala that Butch Cassidy/Sundance Kid movie, a bundle of the money from the safe was actually recovered two feet into the ground at the time. One of the money bags, emptied, was found tucked into the trestle support over the river indicating the bad guys went back that way on their escape.
Now would you require old maps or current maps, or would a combination be best?