James A. Gagliano is a CNN law enforcement analyst and a retired FBI supervisory special agent. He also serves as an adjunct assistant professor at St. John’s University in Queens, New York. Follow him on Twitter @JamesAGagliano. (CNN)While in Mesa, Arizona on a business trip for his Texas-based pest control company in 2016, Daniel Shaver was slaughtered in a hotel hallway. And though the Arizona jury that acquitted the officer, 27-year-old Philip “Mitch” Brailsford, of second-degree murder and reckless manslaughter charges may have gotten it right according to a legal standard, a confluence of interrelated errors by the tactical team transpired to cause this tragedy, and it was entirely preventable.