runner not tagging on fly ball

Question
there's one out. runners on 2nd and third. batter hits a fly ball and the runner on third tags and scores. the runner on 2nd scores also on the play, but clearly left too soon. the catcher realizes this and tags the second base runner after he crosses the plate. does the first run count?

Answer
David,

The catcher's tag on the second runner does not put that runner out.  In order to put the 2nd runner out, the defensive team must appeal the play.  The pitcher must throw back to second before pitching to the next batter.

The first runner's run will score.  The appeal play does not prevent that run.  The out is made after the run scores.

Hope this helps!

Brian