The 2010 book Delay, Deny, Defend: Why insurance companies don’t pay claims and what you can do about it has become a bestseller on Amazon in the week since the murder of UnitedHealthcare CEO Brian Thompson.The book’s title is reminiscent of the three words carved into the bullet casings — “deny,” “defend,” “depose” — found on the Midtown Manhattan street where 50-year-old Thompson was fatally shot on December 4. Luigi Mangione, 26, has been charged with murder in connection to Thompson’s death.