Force play/tag play

Question
1 out, girl on 1st. ball hit to my shortstop, who traps the ball. she thinks she catches it, throws it to 1st and makes the out. the girl running from 1st has now reached 2nd. she turns around thinking the ball was caught and goes back to 1st. my girl at 2nd now has the ball. she runs to 1st and tags the girl out.  the ump said the girl that went back to 1st was safe since the out was made at 1st initially, she was not forced to run and was able to go back to 1st.  i disagree.  i believe she was forced to run and should have been at 2nd or we could have tug her out.

Answer
Hi Patti,

Once the B-R is put out at 1st there is no more force on any runner, it is removed.  R1 can return to 1st if they wish and if standing on the base can not be put out by being tagged.

BTW the PU should have come up with a forceful "TRAP" or something similar so everyone knew the ball was not legally caught.  Runners and fielders should not have to guess.

Mark