II think it's obvious that the "outside PI firm" wasn't Day's brother but was initiated by Vegas.
Three facts that we know:
1. On August 25, 2023, the Big Ten Conference retained U.S. Integrity (USI) "to enhance monitoring efforts and provide additional educational resources to help prevent student-athletes, coaches, and staff from engaging in prohibited sports wagering.... USI will provide integrity monitoring, educational, and social media monitoring services to the Big Ten Conference via its proprietary dashboard. USI conducts analysis across dozens of data sets to proactively identify irregular contest-level, officiating and wagering patterns."
2. On October 17, 2023, an "outside investigative firm" notified the NCAA of a potential prohibited sign stealing scheme conducted by members of the Michigan football staff. The scheme allegedly involves Connor Stalions (and persons hired by him) attending opponents' games and filming their signs from coaches to players.
3. The as yet unnamed whistleblower came from inside UM football program.
Four things that I suspect:
1. After being hired by the Big Ten, U.S. Integrity held meetings with coaches and related personnel from each Big Ten program to explain USI's role and to ask staff members to report any suspicious activity to USI.
2. The UM whistleblower contacted USI and gave them significant information concerning the sign stealing scheme.
3. USI used some of the information obtained from the whistleblower to confirm the sign stealing scheme, probably by sending operatives to games to observe the sign stealing in real time.
4. USI took the information received from the whistleblower, along with the information obtained by their own operatives, and delivered it to the NCAA.
What I really want to know:
1. Did "Vegas" request that the Big Ten hire USI because they detected unusual results from UM football games (for example, covering the spread over 70% of the time)?
2. Did the Big Ten hire USI because opposing coaches complained to league officials about UM "cheating"?
3. With the influx of NIL money and the broad legalization of sports wagering, did the Big Ten hire USI as a routine protective measure against betting shenanigans, and the UM sign stealing scheme was discovered more or less by chance?
The short time between the hiring of USI and the "outside investigative firm" notifying the NCAA of the UM sign stealing scheme (less than eight weeks) suggests that someone may have known that something shady was going on inside Schembechler Hall.