I’ve encountered highly reliable accounts that during the mid-20th century a Beis Din would authorize someone to kill (as in put to death) people. There are situations where force would be allowed and where a Beis Din could use force.
Considering the accounts in the newspapers are of individuals offering their services for a fee, rather than of a Beis Din encouraging or directing people to act, the issue isn’t raised by the case that is causing the discussion. Three frum “hit men” do not make a Beis Din.
Whether a woman would be allowed by halacha to hire “hit men” to deal with a husband who has abandonned the marriage but refuses to write a “get” is a totally different question, and the validity of a “get” written by a husband out of fear his wife would use force against him is still another issue.