Daniel Dluzneski served with the U.S. Secret Service for over 24 years, including as a K-9 Technician with his dog Korak.
After retiring, he worked for the Pinellas County Florida School system, as the Emergency Manager and was responsible for the safety of over 100,000 students in 140 schools.
Here's the title & Amazon link to his book- "The First 5 Minutes"
https://www.amazon.com/s?k=daniel+dluzneski&crid=FSGZH58LLQRZ&sprefix=%2Caps%2C87&ref=nb_sb_ss_recent_1_0_recent