I am unable to make the connection between WilmerHale, Pinkerton, and the Saint Valentine's Day Massacre (a la 1929) as there seems to be none. Are you implying WilmerHale has a connection to the type of notoriety of a gang slaying?
https://en.wikipedia.org/wiki/Haymarket_affair
While WilmerHale may not have a direct connection to actually cracking heads open, their current methods were picked directly from the Pinkertons in the 1970s.