Force Out & Tagging Runner

Question
There was one out and the bases were loaded.  The batter hit a ground ball
which the 1st baseman fielded, tagged the base (second out) and then threw
it to home.  The catcher caught the ball and the runner was called out (third
out).  Apparently the catcher did not tag the runner, so the coaches of the
other team convinced the umpire to declare the runner safe.  The reason they
claimed that once we got the player on 1st out that it was no longer a force
play even though runners were on 3rd and 2nd.  Wasn't the runner on 3rd
base forced to run home, and if so is tagging the runner necessary?

Thank you.

Answer
Nikki,

Yes, even though the batter runner was called out, the runner from 3rd base is still forced to advance because they have lost the right to occupy that base once the batter runner force the following runners to advance.  In this instance, the runner must be tagged.

I hope this has answered your question.  Should you have any other ones, please feel free to write.

-Martin Hoover